Assessment of commercial fruit crop potential of selected banana (Musa sp.) cultivars in the subtropics of coastal Alabama

by Edgar Louis Vinson, III

A dissertation submitted to the Graduate Faculty of

Auburn University In partial fulfillment of the

Requirements for the Degree of Doctor of Philosophy

Auburn, Alabama

May 8, 2016

Keywords: Banana, subtropical, phenology, Musa, non-Cavendish

Copyright 2016 by Edgar Louis Vinson, III

Approved by

Elina D. Coneva, Chair, Professor of Horticulture Joseph M. Kemble, Co-chair, Professor of Horticulture

Esendugue G. Fonsah, Professor Agricultural Economics, University of Georgia Penelope M. Perkins-Veazie, Professor of Horticulture, N.C. State University

Jeff L. Sibley, Professor of Horticulture Floyd M. Woods, Associate Professor of Horticulture

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Abstract

Global demand and increased adaptability of banana cultures has led to the

development of a potential niche market for non-Cavendish bananas. This present work

was conducted to determine the feasibility of producing banana fruit in the coastal region

of Alabama, USA. In the seasons leading to fruit production, several banana cultivars

demonstrated suitability for production due to vigor that was similar to banana cultivars

produced in other subtropical regions. In the first season cultivars ‘Veinte Cohol’ and

‘Ice Cream’ produced significantly more leaves (39 and 38 leaves-1 plant respectively)

than all other medium height banana cultivars. Overall ‘Cardaba’ and ‘Ice Cream’ had

the highest number of leaves present (NLP) and produced the highest total number of

leaves (TLN). Several cultivars produced mature bunches by the end of the 2015 season:

‘Cardaba’, ‘Gold Finger’, ‘Double’, ‘Grand Nain’, and ‘Sweetheart’. Preliminary

findings in cover crops studies have found no increase in soil carbon or organic matter

supplied by Hairy Vetch or Crimson Clover and had no significant effect on growth of

‘Mysore’ banana plants compared to the bare ground treatment. Reflective mulch

treatments resulted in yields that were consistently, numerically higher than the control

treatment but these differences were not significant. Several cultivars have exhibited

adaptability to the gulf coast region of Alabama and hence hold promise as being part and

parcel of a banana niche market. More research must be conducted such as extended

phenological studies and a precise determination of responses to critically low

temperatures to assess banana cultivar’s ability to produce mature bunches before the first

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frost in coastal Alabama, and the effect of innovative cultural practices to reduce inputs

and increase sustainability.

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Acknowledgments

The author thanks his Sovereign God for the people who have helped along this

journey. The author thanks his graduate committee: Dr. Elina Coneva, Dr. Joe Kemble,

Dr. Floyd Woods, Dr. Jeff Sibley, Dr. Penelope Perkins-Veazie and Dr. Chief Esendugue

G. Fonsah for their wisdom, guidance, encouragement, giving of their precious time and

sharing their wonderful gifts. The author greatly appreciates the help of fellow graduate

students, Andrej Svyantek and Roy Langlois for their help with labor, suggestions and

support. It is appreciated by the author more than they will probably ever know. The

work here would not have been possible without the hard work and commitment of the

staff of the Gulf Coast Research and Extension Center, Fairhope, AL.: Mr. Malcomb

Pegues, Director, Mr. Jarrod Jones, Assistant Director, Mr. Bryan Wilkins, Horticultural

specialist, and all of the crew members that helped make the work lighter. The author is

also indebted to the entire Department of Horticulture for their support, well wishes, and

positive, kind words. Lastly the author thanks his wonderful wife and children, Joyce

Thomas-Vinson, Jared and Adriel for their loving support and constant reminders that we

‘can do all things through Christ which strengthens’ us.

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Table of Contents

Abstract……………………………………………………………………………....……ii Acknowledgments………………………………………………………………………..iv List of Tables………………………………………………………………...………….viii List of Figures………………...……………………………………………………........xiii Chapter I: Introduction and Literature Review…………………..…………………….....1 Introduction……………………….………………………………………….……1

Phenological and Morphological Factors…………………………………………7

LER………………………………………………………………….…….7 LAI………………………………………………………………….……..8 Number of Standing Leaves…………………………………………..…...9 Planting to harvest duration (PTH)………………………………….…….9 Pseudostem height……………………………………………………….10 Other Influences of Banana Plant Vigor and Flower Emergence………………..13 Water requirements and irrigation……………………………………….13 Planting Density………………………………………………………….15

Diseases and Nematodes…………………………………………………17

Research and Concepts of Reduced Inputs and Plant Cycle Duration Reduction...…………………………………………………………………..19

Cover Crop Usage Promote Sustainable Production of Banana and

Plantains…………………………………………………………........19

Improve light penetration in lower canopy leaves……………………….23

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Determination of pseudostem survival of low temperatures…………….24

Conclusions………………………………………………………………………30

Literature Cited…………………………………………………………………..32 Chapter II: Exploring the use of Cold-Tolerant Short-Cycle Banana

Cultivars for Fruit Production in Coastal Alabama……..…………..….……….…..42

Introduction……………………………………………………………………..43 Production of Banana Fruit in Alabama………………………………….45 Health Benefits of Banana Fruit………………………………………….47 Materials and Methods…………………………………………………………..49 Statistics………………………………………………………………….51 Results and Discussion………………………………………………………….52 Floral initiation, yield, and bunch characteristics of the R3 crop…………57 Survivability……………………………………………………………...59 Conclusions……………………………………………………………………..60 Literature Cited………………………………………………………………….63

Chapter III: Concepts to Improve Sustainability of non-Cavendish bananas cultivated in the subtropics of Coastal Alabama...……………...……….………………….……118

Introduction……………………………………………………………………..121 Innovation one: Reflective Mulch……………………………………...123 Innovation two: Cover Crop Usage…………………………………….124 Materials and Methods………………………………………………………………….126 Reflective Mulch………………………………………………………………..126 Cover Crop…………………………………………………………………...…128 Statistics………………………………………………………………………...130

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Results and Discussion…………………………………………………………………130 Reflective Mulch………………………………………………………………..130

Discussion……………………………………………………………......…………132 Cover Crop Experiment………………………………………………………...133

Clover Treatments………………………………………………………………134 Discussion………………………………………………………………………………135 Conclusions……………………………………………………………………………..137

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List of Tables

Chapter II:

Table 2. 1. P-values of interaction terms of dwarf, medium, and tall banana Cultivars…..……………………………………………… ………………..……67

Table 2. 2. Pseudostem length (cm) of dwarf (Musa AAA (Cavendish subgroup))

bananas cultivated at the Gulf Coast Rec, Fairhope, AL – parent crop 2013………………....…...………………………..………….………..…………68

Table 2. 3. Pseudostem circumference (cm) of dwarf (Musa AAA (Cavendish

subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013..…………………………………………….…69

Table 2. 4. Height: circumference ratio of dwarf (Musa AAA (Cavendish subgroup))

bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013.……………………………………...……………………………...…….…70

Table 2. 5. Pseudostem circumference (cm) of dwarf (Musa AAA (Cavendish

subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013.........……….……………………………….…71

Table 2. 6. Length and width (cm) of the third-position lamina of dwarf

(Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013.. …………....………......….……………….…72

Table 2. 7. Leaf area index (LAI) of dwarf (Musa AAA (Cavendish subgroup))

bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013…..............................................................................................................…73

Table 2. 8. Leaf emergence rate (LER) of dwarf (Musa AAA (Cavendish subgroup))

bananas cultivated at the Gulf Coast REC, Fairhope, AL – Parent Crop 2013………………………………………………………………………..……..74

Table 2. 9. Cumulative leaf number (CLN) of dwarf (Musa AAA (Cavendish

subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013……..……...…………....………......…………………………………….…75

Table 2. 10. Pseudostem length and circumference at each sampling period of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL, R1 crop, 2014……….......….………………………….…76

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Table 2. 11. Mean height:circumference at each sampling period of dwarf (Musa

AAA(Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL R1 crop 2014......……......……………………………………………...….…77

Table 2. 12. Mean number of standing leaves (NSL) of dwarf (Musa AAA

(Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014………………………………………………….…78

Table 2. 13. Mean laminal length and width at each sampling of dwarf (Musa AAA

(Cavendish Subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……….…....………................................…………79

Table 2. 14. Leaf area index (LAI) and LER each sampling of dwarf (Musa AAA

(Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014.................................................................…………80

Table 2. 15. Cumulative leaf number (CLN) of dwarf (Musa AAA (Cavendish

subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……………..……….……………....…………..…81

Table 2. 16. Pseudostem length (cm) and circumference (cm) of medium height

non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014…..…......………................................……..…...…82

Table 2. 17. Height:circumference ratio of medium height non-Cavendish (Musa sp.)

bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……………….………………………..….…….…83

Table 2. 18. Number of standing leaves of medium height non-Cavendish (Musa sp.)

bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014.…………………………...……………..……...…84

Table 2. 19. Laminal length of medium height non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……………....85 Table 2. 20. Laminal width of medium height non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014….…………….86 Table 2. 21. Leaf area index (LAI) of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014 ……..…...87 Table 2. 22. Leaf Emergence Rate (LER) of Medium Height non-Cavendish (Musa

sp.) Bananas Cultivated at the Gulf Coast REC, Fairhope, AL – R1 Crop 2014……………………………………………...….....88

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Table 2.23 Cumulative leaf number (CLN) of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014..…………………………………………………………………………..…89

Table 2. 24. Pseudostem length and circumference of tall non-Cavendish (Musa sp.)

bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013…………………………...………………..…….……….90

Table 2. 25. Height: circumference ratio of tall non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013……..……..91 Table 2. 26. Number of leaves present of tall non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013………..…..92 Table 2. 27. Laminal length (cm) and width (cm) of tall non-Cavendish (Musa sp.)

bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013……………………………………………………………………....…..…..93

Table 2. 28. Leaf area index (LAI) of tall non-Cavendish (Musa sp.)bananas

cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013.. . . . . ….…94 Table 2. 29. Leaf emergence rate (LER) of tall non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013 ....………...95 Table 2. 30. Cumulative leaf number (CLN) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013………96 Table 2. 31. Pseudostem length (cm) and circumference (cm) of tall non-Cavendish

(Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014………………………………………………..…..97

Table 2. 32. Height: circumference ratio of tall non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……….... ……98 Table 2. 33. Number of standing leaves (NSL) of tall non-Cavendish (Musa sp.)

bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……………………………………………………………………………....99

Table 2. 34. Laminal Length (cm) of tall non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014……………...100 Table 2. 35. Laminal width (cm) of tall non-Cavendish (Musa sp.) Bananas

cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014…...…...….…101 Table 2. 36. Leaf area index (LAI) of tall non-Cavendish (Musa sp.) bananas

cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014…………...…102

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Table 2. 37. Phenological comparisons at flower emergence (TLN) of dwarf,

medium and tall Cavendish and non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R2 crop 2015….………………………………..………………………..………….…...103

Table 2. 38. Comparison of bunch characteristics of dwarf, medium height and tall

Cavendish and non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R2 crop 2015.. .. . . . . . ......……………………….....….104

Table 2. 39. Mean survivability (%) of dwarf, medium and tall Cavendish and non

Cavendish bananas cultivated at GREC, Fairhope, AL………....……………...105 Chapter III:

Table 3. 1. Effect of Silver Reflective Mulch and White Reflective Mulch on Yield

and Production Efficiency of Musa (AAB) ‘Mysore’ Bananas at the Gulf Coast REC Fairhope, AL. 2013………….………………..….………...……………..145

Table 3. 2. Effect Silver Reflective and White Reflective Mulch on Bunch

Characteristics of Musa (AAB) ‘Mysore’ Bananas at the Gulf Coast REC, Fairhope, AL. 2013………….…………..…....………………………………...146

Table 3. 3. The Effects of Silver Reflective Film and White Reflective Mulch on

Pseudostem Length, Pseudostem Circumference,and Height: Circumference Ratio on Musa sp. (AAB) ‘Mysore’Banana at the Gulf Coast REC, Fairhope, AL…………………………………...…………………..…………...147

Table 3. 4. The Effects of Silver Reflective Film and White Reflective Mulch on

Leaf Area, Number of Leaves Present, Cumulative Leaf Number and Leaf Emergence Rate on Musa sp. (AAB) ‘Mysore’ Banana at the Gulf Coast REC, Fairhope, AL…………………………………………………….......……….....148

Table 3. 5. Light Reflectance of white fabric and silver film as measure by

photosynthetically active radiation (PAR). Gulf Coast REC, Fairhope,AL…....149 Table 3. 6. Spad Reading and Net Photosynthesis of the 2nd, 4th , and 8th Lamina of

Musa sp. (AAB) ‘Mysore’ Banana at the Gulf Coast REC, Fairhope, AL……..150 Table 3. 7. Effect of Silver Reflective and White Reflective Mulches on

Timing of Flower Emergence of Musa (AAB) ‘Mysore’ Bananas at the Gulf Coast REC, Fairhope, AL. 2013.. . . . . . . ..……...…………..………...…151

Table 3. 8. Fresh weight, dry weight, %N and %C of crimson clover (CC),

hairy vetch (HV), and Bahia grass (BG)sod control plots at the Oak Hill Tree Farm, Grand Bay, AL, May, 2015………...…………………….152

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Table 3. 9. First analysis of elemental soil nutrient composition of

experimental plots containing Crimson Clover (CC), Hairy Vetch (HV), and Bahia grass (BG) control treatments at the Oak Hill Tree Farm, Grand Bay, AL, November, 2013…….......…………..………..…………….…153

Table 3. 10. Second analysis of elemental soil nutrient composition of

experimental plots containing Crimson Clover (CC), Hairy Vetch (HV), and Bahia grass (BG) control treatments at the Oak Hill Tree Farm, Grand Bay, AL,– November, 2014………...……...………...……………….…154

Table 3. 11. Foliar nutrient composition of bananas cultivated in Crimson

Clover (CC), Hairy Vetch (HV), and Bahia grass (BG) sod control treatment at the Oak Hill Tree Farm, Grand Bay, AL, 2014.. . . . . . . ………………………155

Table 3. 12. Effect of Crimson Clover and Hairy Vetch Treatments on growth

parameters of ‘Dwarf Orinoco’ Bananas in Grand Bay, AL, 2014.. . . . . . . ….156 Table 3. 13. Production Area of Organically Produced Bananas

of Leading Countries in Latin America and the Caribbean…………………….157

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List of Figures

Figure 2. 1. Anatomy of aerial vegetative portions of a banana plant……………………………………..........………….…….........….106

Figure 2. 2. Anatomy of a banana bunch without the bell or male bud….…........…107 Figure 2. 3. Long-Term Mean Monthly Maximum and Minimum Temperatures in Fairhope, AL, USA……………………………………………………………..108 Figure 2. 4. Emerged flowers of inflorescence of banana cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL…………………………………109 Figure 2. 5. Dwarf banana cultivars 12 weeks after DFM at the Gulf Coast Research and Extension Center, Fairhope, AL……………………………………………110 Figure 2. 6. Ambient and soil temperatures in banana field From July, 2013 through

November, 2014 at the Gulf Coast Research and Extension Center, Fairhope, AL……………………………………………………………………111

Figure 2. 7. Bananas regenerated from the rhizome in May, 2015 after

uncharacteristically low temperatures in late December, 2013 and early January, 2014at the Gulf Coast Research and Extension Center, Fairhope, AL…………112

Figure 2. 8. Banana cultivars which belong to the Cavendish subgroup cultivated at

the Gulf Coast Research and Extension Center, Fairhope, AL…………………113 Figure 2. 9. Laminal leaf shredding due to high winds of banana cultivated at the Gulf

Coast Research and Extension Center, Fairhope, AL….……………………….114 Figure 2. 10. Developing bunch from Double (AAA) dwarf banana cultivars

cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL...…115 Figure 2. 11. Harvest banana bunch from Grand Nain (AAA) banana cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL…………………….116 Figure 2. 12. Developing Cardaba banana bunch prior to harvest in December, 2015at

the Gulf Coast Research and Extension Center, Fairhope, AL…………………117 Figure 2. 13. Developing bunch from a Gold Finger (AAAB) exhibiting symptoms of

chill damage prior to harvest in December, 2015 at the Gulf Coast Research and Extension Center, Fairhope, AL……….……………………………………….118

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Figure 2. 14. Developing bunch from Sweetheart (AABB) cultivar prior to harvest in

December, 2015 at the Gulf Coast Research and Extension Center, Fairhope, AL…………………………………………………………………....119

Figure 3. 1. White reflective mulch used to increase light interception of lower

Canopy leaves…………………………………………………………………..158 Figure 3. 2. Silver reflective mulch used to increase light interception of lower

canopy leaves…………………………………………………………………...159 Figure 3. 3. Control treatment with no reflective fabric or film

cover…………………………………………………………………….……..160

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Chapter I

Introduction and Literature Review

Introduction

Bananas are imported to the US primarily from plantations in the tropics:

Ecuador, the Philippines, Costa Rica, and Colombia (Kopel, 2008), but development of

cold-tolerant and short-cycled banana cultivars has led to increased adaptability and

expansion of banana fruit production beyond the ideal growing conditions characteristic

of the tropics into the more variable climates of the subtropics (Daniells and O’Keefe,

2012; Lahav and Lowengart, 1998).

Bananas are produced in several nations in the subtropics such as Egypt, Israel,

Jordan, Create, Cyprus, Turkey, Lebanon, Arabia, Yemen, Oman, Canary Islands,

Madeira, Southern Taiwan, Peoples Republic of China, Asia north of 20° latitude, and

Brazil south of 20° latitude (Stover and Simmonds, 1987).

Furthermore, convergence of key socio-political, economic, and environmental

developments reveals the unique potential of bananas as a specialty crop in Alabama.

Campaigns such as Buy Fresh Buy Local conducted by the Alabama Farmers Market

Authority and promoted for the sake of crop diversity and increased economic

sustainability of farm operations encourages production of non-traditional crops and

consumption of fresh produce with health promoting qualities by consumers (Fonsah et

al., 2005; Lu et al., 2000; www.fma.alabama.gov). Additionally, the Cavendish banana, a

subgroup of bananas that were selected by multinational corporations as the market

2

standard because of its resistance to Panama Disease (Fusarium oxysporium Cubense)

dominates the banana market. This singular focus on Cavendish bananas presents

opportunity for creation of a niche market for non-Cavendish bananas in coastal

Alabama. Moreover the climate in coastal Alabama is mild (USDA Hardiness Zone 8b)

and is conducive for banana fruit production. At the Gulf Coast Research and Extension

Center (GCREC) in Fairhope, Baldwin County, AL, 30° 31’ 35.018’’ North,

87°53’44.473’’ West) mean monthly maximum temperatures are within the cardinal

temperature range for bananas for 7 months during the year (Alabama Mesonet Data

2008-2012) with mean temperatures slightly above range from mid-June to mid-August.

Cardinal temperatures for bananas production fall in the range of 57° F- 88°F with

optimal range of 72° F - 88° F (Robinson, 1996).

Lastly, bananas are the leading import fruit crop in the US and fourth most

important crop globally. US banana import value rose from $1 billion in 2006 to nearly

$2 billion in 2010 while global banana production was cited at over 100 million metric

tons – a 33% increase since 2005. Moreover, bananas are an important source of food

and fiber in many cultures that have a growing presence in the US creating further

demand for banana specialty markets within the agricultural sector.

Bananas (Musa Sp.) are monocotyledonous, herbaceous, evergreen perennial

plants, the fruit of which are imported to the US primarily from plantations in the

Caribbean (Kopel, 2008; Lessard, 1992). However, bananas have a center of origin in

southeastern Asia and the western Pacific and secondary center of origin in Africa

(DeLanghe et al, 2009; Robinson, 1996). Bananas belong to the order Zingiberales and

the family Musaceae. The family Musaceae is composed of only two genera Musa and

3

Ensete. Musa is comprised of five sections that are based on chromosome number and

morphology of inflorescence (Pillay et al., 2012; Stover and Simmonds, 1987). These

sections are Eumusa (2n= 22 chromosomes), Rhodochlamys (2n = 22 chromosomes),

Australimusa (2n = 20 chromosomes), Callimusa (2n = 20 chromosomes), and

Ingentimusa (2n = 14 chromosomes). Since the formation of these classes, however,

technological advances in molecular biology such as amplified fragment length

polymorphism (AFLP), restriction fragment length polymorphism (RFLP), and

chloroplast analysis provide reason to merge Rhodochlamys and Eumusa and Callimusa

and Australimusa (; Irish et al., 2014; Pillay et al., 2012). Eumusa is considered the most

ancient and diverse section and includes desert bananas along with cooking bananas and

plantains while Australimusa consists of the parthenocarpic and edible Fei´ bananas and

Callimusa along with Rhodochlamys consist only of ornamental types (Pillay et al., 2012;

Purseglove, 1972).

The genetic background of bananas which led to the development of domesticated

fruit has been speculated (Simmonds, 1962) but as described by Robinson (1996) wild,

diploid, subspecies of Musa acuminata Colla, hybridized and produced female sterile

diploid (2n = 2x = 22) and triploid (2n = 3x = 33) plants, which produced parthenocarpic

and edible fruit. Diploid and triploid hybrids of M. acuminata were transported to India

and the Philippines and hybridized with a native wild banana M. balbisiana. This

interspecific hybridization resulted in diploid and triploid crosses of M. acuminata x M.

balbisiana. Because of the myriad of clones of edible bananas that have been derived

from both M. acuminata Colla and M. balbisiana Colla a single scientific name cannot be

given, hence , an international system was employed to avoid confusion: Bananas are

4

first referred to by the genus Musa followed by the letter designations that indicate

genome group (A for acuminata and B for balbisiana) and ploidy level (AAA means

triploid with entire genome from M. acuminata) (Purseglove, 1972; Simmonds, 1987;

Lessard, 1992). The major groups of bananas are AA, BB and AB (diploid); AAA, AAB,

and ABB (triploid); AAAA, AAAB, AABB, and AAAB (tetraploid) (Irish et al., 2014;

Ravi et al., 2014; Robinson and Galán Saúco, 2010; Stover and Simmonds, 1987).

Significant variability is sometimes found among cultivars within a genomic group

leading to further classification by subgroup. Genomic group is followed by subgroup (if

any) which is finally followed by the cultivar name. For example, Musa AAA

(Cavendish subgroup) ‘Williams’ indicates that the genome of this banana plant is 100%

Musa acuminata, it is triploid, from the Cavendish subgroup and the cultivar name is

‘Williams’. Similarly, Musa AAB (plantain subgroup) ‘Horn’ indicates that the banana

plant is triploid with 2/3 of its genome from M. acuminata and 1/3 from M.balbisiana . It

is from the plantain subgroup and the cultivar is ‘Horn’. A banana plant with the

designation of Musa AB ‘Ney Poovan’y, means that it is diploid with 50% of its genome

from M. acuminata and 50% from M. balbisiana. The cultivar name is ’Ney Poocan’ y.

No subgroup is given.

Notwithstanding, expansion of geographical boundaries of banana production due

to increased adaptability to abiotic stresses, banana phenology depends to a large degree

on both climatic and edaphic conditions which, if suboptimal, will not only result in

reduced ornamental appeal but also increased cropping cycle intervals as a result of

delayed flower emergence (Fonsah et al., 2004; Robinson, 1996; Surendar et al., 2013;

Zhang et al., 2011). Extreme shifts in temperature and uneven rainfall distribution occur

5

regularly in the subtropics and can affect flowering and ultimately dictate where and how

banana plants can be grown (Smith et al., 1998). Environmental factors: Temperature,

water supply, light, humidity, and soil structure will impact the rate of various processes

in the banana plant (Turner, 1995). These conditions are consistent and conducive for

year-round banana production in the tropics but some become limiting in the subtropics

which typically delays flowering and forces the completion of the banana plant life cycle

to span the equivalent of two growing season of the typical annual temperate crop.

Flower initiation occurs without evident visual cues, but it is accepted the flower

initiation typically occurs after the accrual of a critical cumulative leaf surface area that

corresponds to the production of 37-46 leaves cycle-1 (Vargas et al., 2008).

In contrast to many fruit crops in more temperate regions that exhibit predictable

flowering and fruiting stages that coincide with particular seasons, banana flowering is

largely unpredictable and seems to be independent of temperature and light (Robinson

and Human, 1998). Added to the unpredictability of flowering is the effect of

environmental conditions which impact flower initiation. Several attempts during the

early and mid-20th Century were made to at least describe the origin and development of

the banana inflorescence but exact stimulus of flower initiation remains unknown (Fahn,

1953; Simmonds, 1959). Despite the mystery that surrounds floral initiation in bananas,

certain changes in the shoot apex of bananas as they transition from vegetative to

flowering stages can be observed. Pre-floral redistribution of growth takes place in the

axis. The tip of the apex grows in length becoming more acute, the apex continues to rise

and as it rises from ground level to a level above existing leaf bases, transition from

vegetative stage to the floral stage has begun. Cells beneath the tunica-mantle of the

6

apex, which are normally quiescent, begin to divide. Growth at the bases of previously

emerged leaves decreases and floral bracts are formed in place of leaf primordia. After

transition to the floral or reproductive stage is complete the extension of the axis follows

the same path as developing and emerging leaves being protruded up the center of the

pseudostem through the top of the plant.

Phenological and morphological responses of banana plants to changes in

environmental conditions are an integration of many processes operating over time and

are measures of plant vigor and hence hastening towards maturity (Turner, 1995; Vinson

et at., 2015; Vuylsteke et al., 1996). Phenological and morphological assessments are

therefore paramount in determining production and economic potential of bananas

cultivated in the subtropics (Robinson and Galán-Saúco, 2010). Phenological studies

provide insight into the developmental process of a crop so that growers can dedicate the

bulk of resources when developmental rates are highest. This serves as a signal as to

when to reduce inputs when development has been slowed. Phenological studies also

reveal most ideal and economically significant cultivars for a region (Cruz da Silva et al.,

2010; Fonsah et al., 2007; Robinson, 1996; Turner, 1995); provides knowledge

concerning planting date so that harvest coincides with a particular market during a

period of low crop volume (Fonsah et al., 2004); and aids in forecasting crop volume and

duration of crop season according to date of flowering (Robinson, 1996). For example

leaf emergence rate (LER), cumulative leaf number (CLN) produced by a plant per year

and the interval between flower emergence and harvest (E-H) are factors used to

determine production potential of bananas. Banana cultivar ‘Dwarf Cavendish’ a cultivar

belonging to the Cavendish subgroup, was shown to produce 25 leaves prior to flower

7

emergence and has an E-H interval of 113-212 days (Kuhne, 1980) and has demonstrated

adaptability to extremes of climate (Kuhne, 1975). Comparatively, another cultivar of

the Cavendish subgroup ‘Williams’ demonstrated increased yield due to the elimination

of a condition known as choke throat which occurs in shorter varieties but also

demonstrated an increase in “November dump”, a condition that is a result of winter time

flower initiation (Fahn et al., 1961; Robinson, 1982). A comparison of ‘Dwarf

Cavendish’ and ‘Williams’ revealed that increased pseudostem height by 44% in the first

ratoon plants (R1) over the original (P) plants, while pseudostem height increased by only

25% in ‘Dwarf Cavendish’(Robinson and Nel, 1985). Additionally, ‘Williams’ produced

more leaves per plant, had a slower LER which combined, resulted in longer cycle times.

During the life of the plant, 26-50 leaves are produced (Stover, 1979; Turner et al., 2007).

Phenological and Morphological Factors

Cumulative leaf number (CLN) range required before the emergence of the

inflorescence varies and has been reported to be 37-46 leaves cycle-1. Previous studies

have found this number to be as low as 25 leaves and as high as 60 leaves (Turner et al.,

2007; Vargas et al, 2008). In the subtropical region of Nelspruit, S.A., a comparison of

LER of banana plants at various densities during the most active growing months was 1.5

– 3.5 leaves month-1. Highest planting density of 2,222 plants ha-1 presented a range of

1.5 – 3 leaves month-1, while the lowest planting density of 1,000 plants ha-1 presented

LER of 2 – 3.5 leaves month-1.

LER

Foliar phenological attributes such as leaf emergence rate (LER), leaf area (LA)

and leaf area index (LAI) are the most important to consider prior to shooting and flower

8

emergence as leaves are the primary interceptors of radiant energy from the sun.

Moreover, LER is the most sensitive measure of soil water status (Kallarackal et al.,

1990; Turner and Thomas, 1998). Soil water deficit of 21 kPa is sufficient to reduce LER

by half while a 40 kPa soil water deficit was necessary to reduce transpiration rate by half

indicating that LER is a more sensitive measure of soil water status than stomatal closure.

Moreover, LER is a measure of the advancement of the plant towards maturity (Turner,

1998). In subtropical climates, banana growth rates are prolonged considerably during

the winter month as evidenced in reduction in LER (Tuner, 1971). Under tropical

conditions leaves emerge every 8.3 d to 12.8 d until the appearance of the inflorescence

and results in the production of 37-46 leaves cycle-1 (Vargas et al., 2008). As the leaf

emerges through the top of the plant, it is fully matured and in a vertical rolled state

known as a “cigar” (Skutch, 1930; Stover and Simmonds, 1987). Management inputs

such as irrigation, fertility and weed control must be adequately applied during periods of

increasing LER. If management is insufficient LER will be slowed and harvest will be

delayed by several weeks or months (Surendar et al., 2013).

LAI

Leaf area is used to calculate the leaf area index (LAI) which is the total leaf area

of a plant or plant canopy per unit area of ground occupied by the plants. LAI indicates

the capacity of a plant or plant canopy to intercept solar radiation and synthesize

carbohydrates using CO2 that is taken into the leaves through stomates. Crop yield is not

correlated with amount of solar radiation received but rather it is correlated with the

amount of light received by the plant canopy (Monteith, 1981). LAI varies depending

9

several factors such as plant size, plant spacing, and season and ranges from 2-5 (Turner

et al, 2007).

Number of standing leaves.

Number of standing leaves (NSL) is a measure of the amount of

photosynthesizing leaf surface area maintained by the plant at any moment in time.

This variable is especially important during bunch development as no more leaves are

produced after flower emergence and a minimum of four leaves is required to mature a

bunch (Robinson, 1996). The life span of individual leaves ranges from 71 to 281 days in

the subtropics and up to 150 days in the tropics (Stover and Simmonds, 1987;

Summerville, 1944). During the life of the plant, 26-50 leaves are produced and 10-14

leaves are present on the plant at single time (Stover, 1979; Turner et al., 2007).

Planting to harvest duration (PTH)

Depending on the locale and cultivar, planting to harvest duration (PTH) can last

from 9 months to as long as 20 months (Fonsah et al., 2004; Robinson, 1996). Along

with yield, consideration should be given to PTH as shorter maturing cultivars can enter

the market sooner and provide reduced liability due to disease incidence as well as

mechanical mishap and damage as a result of climate (Cruz da Silva et al., 2010; Fonsah

et al., 2004). In tropical climate of Roraima, Brazil, along with other developmental

parameters, PTH of several cultivars was analyzed. The cultivar ‘Nanicão’ exhibited one

of the longest PTH - 296 d. ‘FHIA-2’ had one of the shortest PTH duration at 234 d.

PTH duration was similar to ‘Prata Anã’ (239.7 d) and ‘Grand Nain’ (241.3 d). In the

subtropical region of Florida, USA, cycle duration was decidedly longer. Banana

cultivars ‘Bom’ and ‘Pelipita’, though they produced a significantly higher bunch weight

10

(6.8 kg and 6.5 kg respectively) than other cultivars exhibited the longest cycling times of

475 d and 500 d respectively. ‘Gipungusi’, demonstrated the shortest cycling time at 343

d (Ayala-Silva et al., 2008). Additionally, bunch development of cold-tolerant, sort-cycle

cultivars had PTH duration of 175 days in Georgia, USA (Fonsah et al. 2007).

Pseudostem height

‘Bom’ exhibited the highest productivity index (100 x bunch weight/ cycling

time) at 1.43 this was followed by ‘Gipungusi’, ‘Pelipita’, ‘Cacambon’ and ‘Blue Torres

Straight Island’ (1.33, 1.30, 1.20, and 0.86 respectively) (Ayala-Silva et al., 2008). Plant

height at 16 months after planting (Krewer et al., 2008) when measured from the base of

the plant to the base of the most recently expanded leaf ranged from 1 m to 1.35 m

among medium height bananas (1 m to 1.49 m) (Fonsah et al., 2004). ‘Grand Nain’

cultivated in this location presented with plant height of 1.06 m which is approximately

that of ‘Grand Nain’ at flowering produced in the tropics of Roraima, Brazil (Ayala-Silva

et al., 2008; Krewer et al., 2008). Shorter plants are more desirable as taller plants are

more prone to lodging due to high winds or heavy crop load (Cruz da Silva et al., 2010).

Method of measuring plant height at this location was not mentioned. Number of leaves

present ranged from 7.5 – 14.6 during the first year and 7.0 – 14.8 the following year.

Low temperature is a major constraint for banana production in the subtropics, the

type of cold weather and stage of plant development play a role (Danielles, and O’Keefe,

2012). There are many differences in response to temperature and these responses to

cold vary genetically – for example optimal temperature for dry matter accumulation for

‘Williams’ is 20 °C while optimal temperature for LER is 30 °C (Turner, 1994).

Furthermore, Musa balbisiana and ‘Highgate’ (AAA) have similar base temperatures for

11

LER and theoretically can be expected to perform similarly in the subtropics; however,

leaves of ‘Highgate’ are more susceptible to low temperatures than Musa balsbisiana and

as a consequence perform poorly (Turner, 1994). Leaves of FHIA-01 (‘Gold Finger’

AAAB) and FHIA-18 (‘Bananaza’ AAAB) remain green a low temperatures and have

higher dry matter accumulation as a rate of higher photoassimilation rates compared to

‘Williams’ (Daniells and O’Keefe, 2012).

Banana plants established in at the University of Georgia Bamboo Farm and

Coastal Gardens in Savanah, GA (USDA hardiness zone 8a) exhibited vigorous growth

and 51% of the total planting flowered and set fruit four months after transplanting

(Fonsah et al., 2010). Cultivars included ‘Novaria’, Blue Torres Straight Island’,

‘Cacambou’, ‘Gold Finger’, ‘Chinese Cavendish’ and ‘Veinte Cohol’. Of these cultivars

‘Veinte Cohol’ was the only cultivar to be considered short cycle because all plants of

this cultivar flowered in sufficient time to reach maturity. Other cultivars ‘Chinese

Cavendish’ and ‘Novaria’ also showed qualities characteristic of short cycle bananas but

more research is needed for a more definitive conclusion (Fonash et al., 2010).

Conversely, a study conducted in the same location revealed that an orchard established

in March did not provide adequate time for fruit production during the first season as the

suboptimal cultural practices, low temperatures and frost converged to delay fruiting in

the initial plant crop (Fonsah et al., 2004).

A banana orchard was established at the Auburn University campus in June, 2011.

All cultivars exhibited tolerance to cold temperatures. Short season cultivars 'Cacambon',

‘Praying Hands’, 'Kumunaba', 'Raja Puri', 'Belle', and 'Kandarian' were included in the

study. In 2012, 'Cacambon' and 'Blue Torres Straight Island' and ‘Praying Hands’

12

bloomed and set fruit. The cultivar 'Cacambon' produced 10-15 fingers per hand while

'Blue Torres Straight Island' produced between 8-14 fingers per hand while ‘Praying

Hands’ produced 3-4 hands with 10-17 fingers per hand. During the 2011-2012 winter

seasons banana plants at the Plant Science Research Center, experienced temperatures in

the mid to low 20’s (ºF). Growth of banana plants resumed the following spring. Flower

initiation and fruit set occurred in nearly 60% of the plants during the second season and

86% the following season. Planting-to-harvest interval ranged from 329 d – 473 d and

405 d – 486 d during the second and third seasons respectively. In 2013, all cultivars,

with the exception of ‘Raja Puri’, bloomed and set fruit. Bunch weight ranged from 3.4 –

3.6 kg. Each banana bunch contained 6 – 7 hands and each hand contained 10 – 16

fingers. Although banana plants survived freezing temperatures during winter and early

spring and most set fruit, only two cultivars flowered with sufficient time to present

mature bunches in the fall before frost in 2012. In Alabama the area presenting the most

potential for successful banana production is along the coast as mean monthly maximum

and minimum temperatures are within cardinal temperature ranges for 7 months during

the year (Alabama Mesonet data 2008-2012) with mean temperatures slightly above

range from mid-June to mid-August (Fig 2). Cardinal temperatures for banana

production falls in the range of 57 °F -88 °F with optimal range of 72 °F – 88 °F

(Robinson, 1996). Thirteen banana cultivars representing three different types were

planted in the coastal region of Alabama in Fairhope on June 5, 2013 as follows: ‘Grand

Nain’, ‘Dwarf Cavendish’, ‘Dwarf Red’, ‘Dwarf Green’ , and ‘Double’ (Dwarf); ‘Gold

Finger’, ‘Viente Cohol’, ‘Raja Puri’, ‘Ice Cream’, and ‘Cordaba’ (medium); and ‘Pisang

Ceylon’, ‘Sweetheart’, and ‘Saba’ (tall). Leaf emergence rate (LER), an important

13

indicator of growth, among bananas were 5.0–5.5, 5.7–7.0 and 6.0–8.0 leaves month-1 in

July, August and September respectively. The leaf emergence rates showed a steady

increase and were similar to leaf emergence rates of banana plants produced in other

subtropical regions around the world with climates similar to the Alabama coast.

Other Influences of Banana Plant Vigor and Flower Emergence

Water requirements and irrigation

Environmental conditions or cultural practices influence date of flowering in

banana by affecting photosynthetic activity. Photosynthetic rate peaks in the morning

followed by saturation deficits in the air, high leaf temperatures and partial stomatal

closure during the afternoon all resulting in reduced photosynthetic rate (Eckstein and

Robinson, 1995a). Therefore, guard cells may close even if leaves are hydrated (Turner

et al., 2007). In order to maintain leaf gas exchange rates soil water potential must not

fall below -15 to -20 kPa range (Eckstein and Robinson, 1996). Additionally, bananas

grown in the subtropics should be irrigated at intervals of one to two days depending on

evaporation rates at a rate of 10 mm d-1 (Robinson and Bower, 1987).

Availability of water can be the most limiting abiotic factor affecting banana

production in subtropical regions (Turner, 1995). In the Canary Islands in ‘Gande Naine’

(AAA Cavendish subgroup) bananas, finger length and diameter were reduced by 9% and

total bunch weight was reduced by 41% from 30 to 17 kg plant-1 when water was

withheld for 63 days following flower emergence (Robinson and Nel, 1989). For

satisfactory growth bananas require 2,000 to 2,500 mm of rainfall distributed evenly

throughout the year which translates into 25 mm per week (Robinson and Galán-Saúco,

2010). Additionally, stomatal behavior, photosynthesis and transpiration were

14

determined as physiological indicators of water deficits in bananas to determine when

irrigation is necessary (Carr, 2009; Robinson and Bower, 1987). The Alabama coastal

region experiences a total annual precipitation of approximately 1,600 mm of rainfall the

majority occurring from rain events distributed in the active growing months (March –

November) and reaching 1,252 mm. this translates into 34 mm of rain each week. Rain

events tend to increase from March – August decreasing slightly from September –

November with the area receiving an average of 14.6 mm rain per event. Despite the

sensitivity of bananas to water deficits, there are few physiological indicators of water

deficits (Carr, 2009). Considerable knowledge of water status has been gained through

determination of physiological responses of plants in general to both atmospheric and soil

water deficits; however, these same physiological responses are not as reliable when the

unusual physiology and morphology of banana plants are considered (Turner et al.,

2007). Moreover, volumetric or thermodynamic tissue water status of lactiferous plants

as in the case of bananas cannot be measured using traditional methods. For example, the

Scholander pressure technique is ineffective because of the inability to distinguish

between sap in the xylem and latex exudates. (Turner and Thomas, 2001). Conversely

measuring the refractive index of the latex exudates was found to be a reliable indicator

(Milburn, 1990; Thomas and Turner, 2001). In ‘Dwarf Cavendish’ (AAA Cavendish

subgroup) stomata experience partial closure beginning four hours before sunset, but

when soil water was depleted by approximately 33% the duration of stomatal opening

occurred later in the day at mid-morning with stomata on the bottom surface closing first

(Shmueli, 1953). When soil water depletion reached 66% stomatal opening occurred

early in the morning and the degree of opening decreased throughout the day with

15

stomata on both top and bottom leaf surfaces behaving similarly (Shmueli, 1953).

Opening of the stomatal aperture is controlled by guard cell turgor and can operate

independently of leaf water status. This is due to the fact that stomata also respond to

water vapor in the air. Moreover, transpiration rates are maintained even when soil water

potential fall to -80 kPa when humidity is high as opposed to -20 kPa in low humidity

(Robinson and Bower, 1987; Shumueli, 1953).

Several studies have been conducted to measure the response of supplemental

irrigation. In New South Wales, an irrigation regime that allowed available water

depletion to reach 10%, 20, 40 and 70% before re-establishing field capacity, through

irrigation using under-canopy sprinkler produced the highest yield in the ratoon crops

when averaged over three years (Trochoulias, 1973). This treatment yielded twice as

much fruit as the rain fed control treatment. This required the addition of 8 mm of water

every 3-5 days when there was no rain. Conversely, on the east coast of Australia, water

regimes that ranged from 0 to 1.20 times Epan at increments of of 0.2 revealed that

irrigation had little effect on yield due to ample rain lessened the need for supplemental

irrigation, but water applied at a rate of 0.6 X Epan is recommended (Trochoulias and

Murison, 1981).

Planting Density

Planting density for bananas is a complex integration of factors such as cultivar,

soil fertility, sucker selection, management level, wind speed and topography that must

be evaluated for each plantation location (Robinson and Nel, 1988). Plant density in a

banana plantation is critical because it determines yield, fruit quality and cycling time and

once it has been set it is not easily adjusted (Langdon et al., 2008). Also, banana in the

16

subtropics should be spaced at a maximum to insure pseudostem temperatures remain

high enough to hinder flowering (Robinson and Nel, 1985). When variations in climate

are considered, the effects of planting density on bananas are more striking. One

characteristic of banana plantations regardless of location is the pronounced increase in

crop cycle duration in response to high planting densities. In studies conducted in the

tropics harvest was delayed as long as 4 or 6 month when crop density was increased 4-

fold or even doubled (Chundawat et al., 1983; Daniells et al., 1985). In the subtropics,

crop cycle in the ratoon crop increased 1.5 – 3 months with 1.5 – 2.5 fold increases in

planting density.

In the subtropics of Australia, ‘Williams’ banana (Musa AAA, ‘Cavendish’

subgroup), in response to increasing plant densities of 1000, 1250, 1666, and 2222

exhibited increased pseudostem height, leaf area, number of functional leaves at harvest

and LAI from the parent crop until the second ratoon crop (Robinson and Nel 1988;

Langdon et al., 2008). Increase in canopy was responsible for the extension in crop cycle

from planting to R3. Bananas planted at a density of 1000 plants ha-1 were able to

complete four crop cycles in the same period bananas planted at 2222 plants ha-1

completed three. LER was reduced by up to five leaves annually with an increase in

plant density from 1000 to 2222 plants ha-1 which resulted in six more leaves produced in

the 2222 plants ha-1 density which allowed only 14% of radiation to through the canopy

beyond the recommended 10% (Turner, 1982; Robinson and Nel 1988). Yield potential

should be related to the characteristics of the canopy and not necessarily crop density

(Robinson and Nel, 1988). Optimal plant density was extrapolated to be from 1800-

2000, but when long-term effects of crops beyond the second ratoon until are considered,

17

a cop density of 1666 plants ha-1 is recommended (Robinson and Nel, 1989). Lower crop

densities are desirable as increased crop densities result in increased plant height,

decreased bunch weight and increased harvest cycles (Langdon et al., 2008).

Diseases and nematodes

Several devastating disease affect the Musa species. These diseases are fought by

application of chemical and planting of resistant cultivars (Heslop-Harrison and

Scharzacher, 2007). Disease is so severe in many regions that planting of GMO

(genetically modified organism) plants are being considered despite the resistance of the

public.

At the dawn of the banana trade and some years preceding, the industry became

highly dependent on a single banana cultivar called ‘Gros Michel’(Musa AAA ‘Gros

Michel’)(Chapman, 1997; Kopel, 2008; Stover, 1962). The cultivar was known for its

ability to produce massive bunches of large fruit that were flavorful and resistant to

mechanical damage (Ploetz, R.C., 2005). Large swatches of land were purchased in the

tropics by Multinational corporations, deforested and replanted with monoculture of

‘Gros Michel’. The cultivar was susceptible to a condition which was known as Panama

disease. Plantations began to be overtaken by the plant malady, which in response waged

chemical warfare. Corporations across the tropics recorded huge losses, some total losses

(Ploetz, R.C., 1992). Chemical warfare was waged against the disease sickening many

plantation workers and hundreds more acres were deforested and replanted with bananas

for a resistant banana, Cavendish (Musa AAA Cavendish), was discovered. Prior to the

discovery of Cavendish bananas many predicted certain and complete ruin of the banana

industry. The causal agent of Panama disease was a fungus Fusarium oxysporum f. sp.

18

Cubense which classifies Panana disease as a type of Fusarium Wilt. F. oxysporum f.

sp. Cubense (FOC) is a vascular disease affecting the roots as well as the corm. Infection

in fact originates in the roots and spreads through the corm and to the pseudostem. It

causes yellowing of older leaves and heavy vascular discoloration.

Fusarium wilt has long been a problem in subtropical regions such as Australia:

Initial findings were in Queensland in 1874 (Smith et al., 1998). In the subtropics

subtropical race 4 (STR4) which occurs as a result of cooler temperatures and suboptimal

production practices has been found in the area (Smith et al, 1998). The disease is also a

significant problem in the subtropics of South Africa, Taiwan, Brazil and Canary Islands

(Daniells and O’Keefe, 2012). FHIA -01 and FHIA 18 are also thought to resistant to

TR4. FHIA-01 (‘Gold Finger’) a released to Australia in 1995, has exhibited resistance

to subtropical race 4 FOC. Other cultivars thought to be resistant to TR4 and STR4 are

‘Bananaza’, SH-3656, and Pisang Ceylon (AAB). Since that time, many other diseases

of bananas and plantains have been discovered. Some of the more economically

important diseases are listed here.

In recent years, another condition is known as Black sigatoka leaf spot or black

leaf streak disease caused by the fungus Mycosphaerella fijiensis has caused significant

crop losses up to 50% (Heslop-Harrison and Scharzacher, 2007). A pale yellow or dark

brown streak 1-2 mm in length appears on the lower surface of leaves. The disease

progresses through several stages with increasing from minute specks to more

pronounced spots along the border of a leave resulting in a streak (Stover and Simmonds,

1987). Currently the disease is controlled through harsh environmentally damaging

chemicals; however, there are some Musa sp with some genetic resistance (Heslop-

19

Harrison and Scharzacher, 2007). FHIA-01 and FHIA-18 have exhibited resistance to

this disease.

Bunchy top is caused by a luteo virus (spherical 25 nm virus particle) and it is

spread via an aphid vector Pentalonia nigronervosa. The disease starts as dark green

streaks in the petiole and leaf veins. Leaves take on an erect posture and are bunch

together at the top of the plant. Cavendish varieties are susceptible but cultivars that have

the ABB genome are resistant (Stover and Simmonds, 1987). Disease is controlled by

removal of the entire mat of the infected plant and replanting with plants from disease-

free regions.

Damage caused by burrowing nematodes (Radopholus similis) is caused by the

secondary invasion of bacteria and fungi that has advanced to the stele as nematode

invasion of the stele is rare (Pinochet and Stover, 1980). There are biological races that

differ in pathogenicity and attack specific hosts (Tarte and Pinochet, 1981). Root rot

caused by fungi weaken developing roots. Anchoring of the plant is consequently

weakened leading to lodging of the plant which is the main reason for economic losses.

Other nematode species of lesser economic importance are Pratylenchus coffeae,

Helicotylenchus multicinctus, Helicotylenchus aricanus and members of the genera

Meloidogyne (root knot nematode), Rotylenchus, Scutellonema, and Hoplolaimus (Stover

and Simmonds, 1987).

Research Concepts of Reduced Inputs and Plant Cycle Duration Reduction

Cover Crop Usage Promote Sustainable Production of Banana and Plantains

Use of cover crops is one of the most important sustainable practices used in

global management strategies in agricultural systems precisely because it improves soil

20

tilth, suppresses weeds and disease, and increases yields of target crops (Lu et al, 2000;

Robinson, 1996, Tixier et al., 2011). Cover crop is defined as perennial or biennial

herbaceous plants used for their ability to cover soil surfaces for all year or a part of the

year (Stone et al., 2005).

Before synthetic fertilizer was developed, cover crops were used to replenish soil

nutrients depleted by main crops (Stone et al., 2005). Though cover crop usage in crop

production is not a new technology, there has been a surge in the incorporation of cover

crops in agricultural systems as it reduces inputs and suppresses pests by reintroducing

biodiversity (Tixier et al. 2011). Some other benefits of cover crop usage are control of

soil erosion, nitrogen fixation, and increased water holding capacity. Growing concern

about the use of pesticides, soil erosion, and depletion of natural resources have prompted

shifts towards more sustainable practices such as cover crop use (Lu et al 2000). A case

study in the Innisfail district in coastal north Queensland, Australia presented by

Bagshaw and Linday (2009) discussed concerns of government and research

organizations concerning farm-sourced pollutants and their damage to natural icons such

as the Great Barrier Reef and World Heritage-listed rainforest area and banana producer

groups’ collective intension to demonstrate good environmental stewardship. The banana

group Better Banana Business Sustainability (BBBS) group identified high priority

environmental areas and practices to mitigate environmental impact. One of the key

practices adopted by the group was the use of cover crops. Cover crop usage provided

members of BBBS reduced labor and fuel costs and preparation time. Reduced

preparation time allowed growers time to manage other areas in their operations.

Planting nematode (Radophilis similis) reduced nematicide usage and reduced sediment

21

and pesticide transport. Intensive cultural practices used in export banana production

systems are usually carried out on bare ground and therefore require large inputs such as

pesticides and fertilizers and the use thereof present challenges for delicate environmental

systems around the world (Bonan and Prime, 2001) Cover crops have been used in

plantation and orchard production where it has mitigated soil erosion, weed infestation

and nutrient leaching due to large plant spacing common to these production scenarios.

Cover crops usage has increased soil organic matter which has led to increased soil

productivity (Baligar et al., 2006). Use of cover crops can lower inputs even when

compared synthetic mulch such as polyethylene. For example, in tomato production,

hairy vetch (Vivivia villosia) required 250 lbs acre-1 less than that polyethylene mulch

(Abdul-Baki and Teasdale, 1997) and provided a savings of $150 acre-1. Over the course

of three seasons, hairy vetch produced higher tomato yields than both polyethylene mulch

and bare soil treatments. At the time of this study, return per acre was expected to exceed

$44,000 compared to $22,000 and $8,000 acre-1 for polyethylene mulch and bare soil

treatments respectively. Profitable farms strengthen rural communities allowing farmers

to in turn reinvest in the community and enhance the local economy. Use a particular

cover crop in an agricultural system must be considered carefully. A suitable cover

should produce sufficient biomass in order to compete with weeds for resources while not

competing with the main crop (Costello and Altieri, 1994; Tixier et al., 2011). In some

instances, cover crops are grown before planting of a main crop. When the cover crop

flowers and produces sufficient biomass it is killed and allowed to decompose. The crop

residue may be incorporated in the soil or remain on the soil surface. When left on the

soil surface, remaining plant residue acts as much as it provides moisture retention and

22

weed suppression. Weed suppression is not only due to the physical barrier of cover crop

but also due to allelopathic effects (Mulvaney et al., 2010). As plant residues decompose,

phytotoxins are released and affect the growth of weeds and potentially the main crop

(Wallace and Bellinder, 1992).

Use of cover crop systems in banana production will involve selecting the most

appropriate species that presents the best trade-off between cover crop/weed systems and

cover crop/main crop systems (Picard et al., 2010). Cover crops are usually evaluated in

terms of yield performance of a main crop in relation to the main crop cultivated on bare

ground (Tixier et al., 2010). Benefits of cover crop usage in agricultural systems are

measured over several seasons and often require several years to determine. To expedite

the selection process of cover crops some studies have employed the use of models to

predict the performance of cover cropping systems (Rioche et al., 2012; Tixier et al.,

2011). Models have been developed to predict weed populations, weed/main crop

interactions, and genotype/environmental interactions (Paolini et al., 2006; Holst et al.,

2007; Wang et al., 2007). A study conducted by Tixier et al. (2011) described the use of

a model-based system for the selection of cover crops in banana production. The authors

developed a model called SIMBA-CC which was based on radiation reception. The

system was calibrated to predict the long-term performance of 11 cover crop species.

The model was used to access cover crop/weed competition, cover crop/banana crop

competition, and longevity of cover crop species grown under the canopy of the banana

crop. In this study cover crops represented three families – Fabaceae, Poaceae, and

Convolvulaceae. The authors found that the most suitable species in terms of their ability

23

to maximize competition with weed species while minimizing completion with banana

crop were Alysicarpus ovalifolius, Cynodon dactylon, and Chamaecrista rotundifolia.

Ripoche et al. (2012) conducted a similar study using a model called SIMBA-IC.

This model simulated nitrogen and light partitioning and cover crop management at

various zones in relation to banana crop placement. In the study the authors assessed

banana yield and N losses in different cover management and fertilization scenarios.

Zones in the banana field consisted of banana rows (BR); small inter-row (SIR) which

was the area between two BRs; Inter-row (IR) which was the immediate area along the

banana row but opposite the BR; and large inter-row (LIR) which was the area separated

from the BR by the SIR. Cover crop treatments used in the study were Brachiaria

decumbens (BD) and Cynodon dactylon (CD). A bare soil (BS) treatment was also

included. The authors determined that simulation results were consistent with actual field

observations and that the impact of cover crop or fertilization on agronomic and

environmental performances can be realistically simulated. They concluded that in order

to strike a balance between nitrogen leaching and banana yield, management practices

should favor N stress in banana crop and consequently minimal reduction of yield.

Improve light penetration in lower canopy leaves

In cooler subtropical regions, the interval between late and early frosts is

comparatively shorter. In order for bananas to reach maturity before the late frost,

shooting and emergence of banana flowers should begin during the month of July

through August in order that there is enough time for sufficient maturity to occur for the

developing bunch. Studies should be conducted that investigate practices that can

potentially decrease cropping cycles so that production of bananas fits within the interval

24

of early and late frosts and conform to an annual cropping system found in crops such as

peach and apple. Plastic mulch and fabrics have previously been evaluated for use in

deterring insects that cause damage to plants or vector disease-causing agents such as

fungi or bacteria. Improved yields of tomatoes were found as a result of colored mulches

(Csizinszky et al., 1995). Aluminum mulches have been shown to repel thrips and aphids

– two important disease-vector organisms (Adlers and Everett, 1968; Brown and Brown,

1992; Wolfenbarger and Moore, 1968). More recently, white reflective fabric improved

light environment, increased photosynthetic activity by as much as 95% and increased

yield by 18% in mature, low-density ‘d’ Anjou’ pear orchards (Einhorn et al., 2012).

Leaves 2 -5 of the banana canopy profile are the most photosynthetically active

(Robinson and Galán Saúco, 2010). Rate of photosynthesis declines from leaf 6 and

below.

Increased planting density improves leaf area index (LAI) of a planting (Robinson

and Galán Saúco, 2010). Increased LAI in turn increases the amount of PAR banana

leaves receive which leads to improved yields. However, delayed cropping cycles and

increased plant height in high density plantings are the result of increased number leaves

and slower leaf emergence rate (Chundawat et al., 1983; Daniells et al., 1985; Robinson and

Nel, 1988; Turner, 1982). Increased light penetration reduces shading which will increase LER

(Robinson, 1996). This is the reason lower density plantings (<2,000 plants ha-1) are desired in

the some regions in the subtropics. Increased intra canopy light interception may also decrease

leaf senescence. Foliar longevity influences the number standing leaves on a plant which can

shorten the cropping cycle by enhancing the amount of dry matter produced. At the time of

bunch formation higher number of leaves present improves maturation of the developing bunch.

Determination of pseudostem survival of low temperatures

25

Banana is a tropical plant that thrives in climates where the mean annual

temperature does not fall below 20°C (Damasco et al., 1997); however, mean annual

temperatures in many subtropical regions fall below 9°C. This presents a significant

hazard to production and indicates that low temperature (LT) is the most limiting

environmental constraint in subtropical climates (Bertamini et al., 005; Boyer, 1982;

Noctor et al., 2002; Zhang et al., 2011). Therefore, controlled environment studies that

involve tolerance of banana plants to absolute minimum temperatures similar to those

that usually occur in the coastal region of Alabama should be conducted.

Range of LT is 0-15ºC for plants that originate from temperate climates and 10-

25ºC for plants of tropical and subtropical origin (Hola et al., 2008). Ideal temperature

for banana production falls in the range of 14 °C -31 °C with optimal range of 22 °C – 31

°C (Robinson, 1996). Alabama’s coastal region boasts potential for successful banana

production owing to the fact that mean temperatures are within the acceptable range for 7

months during the year (Alabama Mesonet data 2008-2012) with mean temperatures

slightly above range from mid-June to mid-August.

Foliar damage to bananas occurs when night temperatures are 0 °C – 6 °C and

results in yellow leaves caused by chlorophyll destruction, while the simultaneous

cessations of LER and plant growth occurs when mean monthly minimum temperature

falls to 9 °C or when mean monthly temperature falls to 14 °C (Robinson and Galán

Saúco, 2010). Additionally, flower initiation that occurs during periods of LT result in

malformed bunches that are reduced in size. This phenomenon was demonstrated in a

study conducted in South Africa. Bunch mass and number of hands per bunch were

reduced by 35% and 23% respectively when flower initiation occurred during the winter

26

in ‘Williams’ (AAA) (). Low temperature reduces photosynthetic capacity through

photoinhibition - a broad term that can suggest a protective, regulatory mechanism in the

phototsystem II (PS2) centers or photo damage to photosynthetic cellular machinery, and

it is a result of photon energy absorbed in excess of the capacity of the electron transport

systems in leaves (Bertamini et al., 2005; Huner et al., 1998). Photoinhibition increases

with decreasing temperatures and increased photon irradiance (Zhang et al., 2011).

Classified among the first symptoms of LT are extensive damage to plants at the cellular

and sub-cellular levels such as damage to key proteins, rupturing of thylakoid membranes

and consequently disruption of photochemical activity through change in the ultra-

structure of chloroplasts (Hola et al., 2008; Zhang et al., 2011). These phenomena that

occur during periods of LT can also result in production of damaging reactive oxygen

species. Reactive oxygen species (ROS) are produced during normal physiological

processes as byproducts of aerobic metabolism (Apel and Hirt, 2004). During long-term

exposure to LT, however, high levels of ROS accumulate in cells in plant leaves (Zhang

et al., 2012). ROS such as peroxide, superoxide, hydroxyl radicals and singlet oxygen

are extremely toxic to plants and react with DNA, proteins, carbohydrates, and lipids and

cause cell death (Zhang et al., 2011).

Plants are able to counter the effects of ROS by both enzymatic and nonenzymatic

scavenging mechanisms; nevertheless, once balance between production and scavenging

of ROS is disturbed by either biotic or abiotic phenomenon, ROS levels rise within cells

which can cause irreversible damage that lead to tissue necrosis and ultimately to plant

death (Apel and Hirt, 2004; Rebeitz et al.,1988). Some plant species such as grape (Vitis

vinifera) and spinach (Spinacia oleracea) have shown some resiliency to LT-induced

27

photoinhibition. The D1 protein center within PS2 complex, often damaged by photo

irradiation, is replaced regularly and it was hypothesized that plants capable of sustaining

adequate replacement rates are able to maintain photosynthetic levels (Andersson and

Aro 2001; Zhang et al., 2011). Likewise, plantain cultivars such as ‘Cachaco’ (Musa

paradisiaca ABB cv. Dajiao) have exhibited tolerance to LT when compared to a dessert

banana such as ‘Williams’ (Musa acuminata AAA cv. Williams) which is susceptible to

LT, (Zhang et al., 2011). When grown in day and night temperature as low as 7ºC,

DPPH scavenging activity was lowered by LT in ‘Williams’ but was unchanged in

‘Cachaco’ (Zhang et al., 2011).

In subtropical regions where mild climatic conditions allow banana production to

continue throughout winter, banana leaf production may simply be slowed or stopped

altogether. However, as a consequence of more marginal climatic conditions in other

regions of the subtropics, wintertime banana production does not occur, as sub-freezing

temperatures render leaf destruction complete and the leaf sheaths, compressed to form

the pseudostem are left to protect the remaining developing leaves within the axis of the

pseudostem as well as subterranean leaf primordia and apical meristem. Banana

production will, therefore, depend on cold tolerance of the pseudostem as new leaves will

be regenerated when environmental conditions become more conducive for banana

production.

Formation of ice crystal in the apoplasts of and between cells is a dehydrative

process because as ice crystals form in the apoplast, water is drawn out of the cytosol.

For example, as much as 90% of osmotically active water is drawn out of cell when

temperatures reach -10 °C (Thomashow, 1999). However, the primary reason for plant

28

death as a result of LT is injury to plasma membranes as a result of expansion-induced

lysis (Smallwood and Bowles, 2002) complicated further by perturbations in electrical

potential or loss of osmotic behavior upon thawing of plant tissues (Thomashow, 1999;

Steponkus, 1984). Plant survival of sub-freezing conditions will depend on the tendency

of plant tissues to tolerate or avoid freezing. Freeze tolerance occurs when ice crystals

are allowed to form in the apoplast. Formation of ice crystals in the apoplast will draw

water out of the cytosol and prevent the formation of ice crystal in this region of the cell,

but sections of membrane must be deleted through vesiculation or conserved through

invaginations to accommodate changing cell volume and return to pre-freeze

configurations as ice thaws (Smallwood and Bowles, 2002). Freeze avoidance prevents

formation of ice crystals in the cytosol through supercooling; however, this strategy is

effective when exposure to subfreezing temperatures is brief as nucleators - initiators of

ice crystal formation, in the environment are abundant (Smallwood and Bowles, 2002).

Certain plant species that have been acclimated to draught conditions have subsequently

exhibited cold tolerance (Serrano et al., 2005; Wong et al., 2005). Changes that occur at

the cellular level as a result of water deficit occur also as a result of exposure to LT

(Medeiros and Pockman, 2011). This is significant because banana cultivars that have

balbisiana as part of their genetic make-up tend to have tolerance to draught and many

factors associated with LT are shared with other abiotic stresses such as draught and

salinity and it has been suggested that expression of cold tolerance may involve several

parallel pathways that can lead to activation of a ‘suite’ of genes involved in tolerance to

LT (Smallwood and Bowles, 2002; Xin and Browse, 2000). Additionally, ABA, if

applied exogenously can impart tolerance to LT in several plant species (Chen et al.,

29

1983). Studies show that ABA levels increase as a response to LT and increases

tolerance to LT (Chen et al. 1983). Also, some studies in LT seem to suggest that

calcium plays a role in cold acclimation. Initially, after expose to LT there is an influx of

calcium ions to the cytosol from the apoplast (Knight et al., 1991; Smallwood and

Bowles, 2002). It has been shown that calcium is necessary for the full complement of

cold tolerance gene expression in Arabidopsis (Kaye et al., 1998).

As part of the assessment of banana production along the coast of Alabama, cold

studies that involve pseudostem tolerance to subzero temperatures should be conducted.

Difference in responses to LT may be found among different banana cultivars. A study

revealed that a clone of ‘Williams’ banana cultivar, W811 exhibited the smallest decrease

in photosynthetic rate and stomatal conductance when compared to three other clones of

the same cultivar after exposure to LT for 48 and 72 h signifying greater tolerance to LT

(Zhang et al., 2012). Therefore greater differences among cultivars from diverse genetic

backgrounds are expected. In relation to LT, plant responses can be categorized in two

ways: Adaptation or acclimation. As previously defined (Huner et al., 1998) adaptation

to LT is the result of genotypic response to long-term exposure and genotypic alterations

as a result of LT are stable and persist in a population throughout subsequent generations.

Conversely, acclimation is a phenotypic response to an environmental factor that doesn’t

result in genetic change initially but, long-term can lead to adaptation. Cold acclimation,

exposure to LT above 0 °C has historically been known to increase tolerance of LT below

0 °C. Previous studies have shown that plants at the cellular level respond less to

absolute temperature and more to changes in temperatures (Minorsky and Spanswick,

1989).

30

Conclusions

Bananas possess unique potential as a specialty crop for Alabama because they

are the leading import fruit crop in the US and they are intrinsic to many cultures which,

through increased immigration, have a growing presence in the US creating further

demand and greater potential for banana specialty markets within the agricultural sector

(Ayala-Silva et al. 2008; Cruz da Silva, 2010; Fonsah et al., 2007). Moreover, Alabama’s

climate along the gulf coast is favorable for production of bananas which have some

measure of cold tolerance and shorter production cycles in comparison to banana

cultivars that are cultivated in the tropics. Alabama and the Southeastern region of the

United States in general have historically been proving ground for several specialty or

exotic crops such as Satsuma mandarin which was introduced to the state in 1898 from

Japan (Ebel et al., 2008) and Kiwifruit, a native of China, commercially produced in

California since the late 1960’s is being tested to determine feasibility for production

(Bernie et al., 2009). Subsequently, kiwi varieties AU Golden Dragon and AU Golden

Sunshine were developed and released through a joint venture between Auburn

University Department of Horticulture and the Fruit and Tea Institute of Hubei Provence,

China. Other crops include Chinese chestnut (Castanea mollissima), Asian pear (Pyrus

pyrifolia), Oriental persimmon (Diospyros kaki), pomegranate (Punica granatum),

Mayhaw (Crataegus Sp), pineapple guava (Acca sellowiana), white mulberry - (Morus

alba) food source for the silkworm moth (Bombyx mori) for production of silk, sisal

(Agave sisalana), cotton (Gossypium hirsutum), and wine grape (Vitis vinifera)

(Lamberts, 1993; Pauly, 2007; Walker et al., 2014). Production of these exotic crops in

the variable and extreme climate of the subtropics encountered varying degrees of

31

success and failure. Banana crops themselves are fraught with innate challenges such as

plant responses to crop density, unique developmental responses to a given climate and

varietal non-conformity over flower initiation which is apparently initiated by an

unknown elicitor without regard to light quantity and temperature. As was with

previously introduced exotic crops, navigating these formidable challenges in the

subtropics will be critical to successful banana production along the coast of Alabama.

32

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Zhang Q., J.Z. Zhang, W.S. Chow, L.L. Sun, J.W. Chen, and Y.J. Chen. 2011. The

influence of low temperature on photosynthesis and antioxidant enzymes in

sensitive banana and tolerant plantain (Musa sp.) cultivars. Photosynthetica

49:201-208.

Zhang, J.Z., Q. Zhang, Y.L. Chen, L.L. Sun, L.Y. Song, and C.L. Peng. 2012. Improved

tolerance toward low temperature in banana (Musa AAA Group Cavendish

Williams) South African J. Bot. 78:290-294.

42

Chapter II

Exploring the Use of Cold-Tolerant Short-Cycle

Banana Cultivars for Fruit Production in Coastal Alabama

A phenological study was designed to determine the feasibility for producing

bananas in the subtropical region of Coast of Alabama. Thirteen Cavendish and non-

Cavendish banana cultivars planted at a 2.4 m x 3 m spacing. Cultivars were separated

according to vigor as dwarf, medium and tall and treated as separate experiments. The

study followed a completely randomized design with 6 single-plant replication.

Pseudostems among dwarf cultivars increased over 100% between 34 days from planting

(DFP) and 59 DFP and by 62% between 59 DFP and 95 DFP. The mean number of

leaves sustained by dwarf cultivars ranged from 5 at 60 DFM to 14 at 208 DFM.

Phyllochron, as measured by LER, ranged from 5 leaves month-1 during the warmest

parts of the season to 1 leaf month-1 when temperatures were cooler. Medium cultivar

‘Cardaba’ consistently produced among the tallest pseudostems while ‘Gold Finger’

produced among the shortest pseudostems. ‘Gold Finger’ typically produced the lowest

height: circumference ratio (HCR) which indicated a stronger pseudostem. Cultivars

were able to support a similar number of leaves (NSL) and a sufficient number of leaves

emerged while ‘Raja Puri’ produced the fewest leaves at each sampling. ‘Saba’ bananas

were theoretically able to intercept more light radiation than ‘Pisang Ceylon’ and

‘Sweetheart’ as indicated by LAI. Pseudostem length of ‘Saba’ bananas was statistically

longer than ‘Pisang Ceylon’ and ‘Sweetheart’ for most of the season. Tall bananas were

43

able to support fewer leaves after mid-season as NSL decreased after this point.

Morphological and phenological characteristics were determined at the time of flower

emergence. Pseudostem length of ‘Grand Nain’ in the current study were 58% shorter

than ‘Grand Nain’ cultivated in the subtropics of the Canary Islands but were 41% taller

than ‘Grand Nain’ bananas cultivated in the subtropical region of coastal Georgia, USA

(Savannah) which is in the same USDA hardiness zone . Both cultivars flowered after a

CLN of 26.2 and 24.4 leaves plant-1 for ‘Double’ and ‘Grand Nain’ respectively. Flower

emergence occurred 15 d earlier in ‘Double (160) than in ‘Grand Nain’ (175). Flower

emergence occurred earliest in ‘Cardaba’ followed by ‘Gold Finger’ (145 d and 166 d

respectively ‘Grand Nain’ had an 83% survival rate while ‘Dwarf Red’ had a 50%

survival rate by the end of 2014. Several cultivars demonstrate potential for fruit

production in coastal Alabama but phenology is notably lacking in the current study

compared to the same cultivars produced in other regions of the subtropics. More

phenological studies are necessary to determine cultivars with the greatest adaptability an

experience floral initiation and bunch maturity prior to early frost in coastal Alabama.

Introduction

Global production of bananas has been cited at over 100 million metric tons since

2005 making it the 4th most important crop in the world (FAOSTAT, 2013). Bananas are

intrinsic to many cultures as they are an important source of food and income and vital to

the economies of developing nations serving a variety of functions such as a source of

starch, dessert fruit, substrate for beer production, livestock forage, shade, roofing and

medicinal purposes (Ayala-Silva et al. 2008; Cruz da Silva, 2010; Ouma, et al. 2010).

Leaves and ancillary portions of the inflorescence are sold at African and Chinese

44

markets in the US (Fonsah et al., 2004). See Figure 2. 1. and 2. 2. for anatomical

descriptions of the banana plant.

Bananas are monocotyledonous, herbaceous, evergreen perennial plants with a

center of origin in southeastern Asia and the western Pacific and secondary center of

origin in Africa (DeLanghe et al, 2009; Lessard, 1992; Robinson, 1996); however,

bananas are imported to the US primarily from plantations in other nations within the

topics such as Ecuador, the Philippines, Costa Rica, and Colombia at low prices (Kopel,

2008). Moreover, development of cold-tolerant and short-cycled banana cultivars has led

to increased adaptability and expansion of banana fruit production into the variable

climates of the subtropics (Lahav and Lowengart, 1998). In the subtropics, bananas are

produced in several nations such as Egypt, Israel, Jordan, Crete, Cyprus, Turkey,

Lebanon, Arabia, Yemen, Oman, Canary Islands, Madeira, southern Taiwan, People’s

Republic of China, Asia north of 20º latitude, and Brazil south of 20º latitude (Stover and

Simmonds, 1987).

Regions of banana fruit production in the subtropics are largely situated between

20° and 30° north and south of the Equator, but production of bananas is met with the

challenges presented by variations between day and night temperature as well as

extremes in seasonal temperatures and uneven rainfall distribution (Smith et al., 1998;

Robinson, 1996). However, banana studies conducted in the subtropics whether they

target commercial banana fruit production, ornamental appeal, optimal plant spacing and

arrangement or cultivar performance, continue to demonstrate potential for banana

production in the subtropics and their marketability in both local and international venues

45

(Denger et al., 1997; Fonsah et al. 2007; Langdon et al., 2008; Lessard, 1992; Robinson

et al., 1996).

Production of Banana Fruit in Alabama

Potential for banana fruit production as a specialty crop in Alabama lies in global

demand, favorable climatic conditions, the need for crop diversity to provide

sustainability to farm operations and significant health benefit supplied to consumers.

Hawaii is the only state in the US that produces Cavendish bananas on a commercial

scale, but non-Cavendish banana fruit has been successfully produced in the southeastern

US in Georgia, Florida and Texas (Fonsah et al., 2004; Krewer et al., 2008;). In fact,

non-Cavendish bananas have been produced in Florida for more than a century (Fonsah

et al., 2004; Ploetz et al., 1999). The banana market in Florida has previously generated

$ 2.5 million annually (Fonsah et al., 2007). In the subtropical region of Florida, cycle

duration was decidedly longer. Banana cultivars ‘Bom’ and ‘Pelipita’, though they

produced a significantly higher bunch weight (6.8 kg and 6.5 kg respectively) than other

cultivars exhibited the longest cycling times of 475 d and 500 d respectively.

‘Gipungusi’, demonstrated the shortest cycling time at 343 d (Ayala-Silva et al., 2008).

Additionally, in Georgia, there is high demand for banana nursery stock and several

banana cultivars demonstrated relative high production of suckers producing 5-6 suckers

per plant. Suckers are separated from the mother plant, containerized and retailed for

approximately $ 15 each. A spacing of 6 m2 plant-1 therefore could potentially earn $

133,000 - $ 160,000 ha-1 for containerized banana plantlets (Krewer et al., 2008). In

Georgia, cold-tolerant, sort-cycle cultivars began producing bunches 25 weeks after

planting (Fonsah et al. 2007).

46

Bananas are the leading import fruit crop in the US where import value rose from

$1 billion in 2006 to nearly $2 billion in 2010. Additionally, the influx of immigrants

into the U.S. and into the state of Alabama specifically helps to create further demand

and greater potential for a banana specialty market within the agricultural sector (Fonsah

et al. 2007).

Cavendish bananas were selected as the sole commercial banana due to their

resistance to Panama Disease (Fusarium oxysporum Cubense) and yield potential by

large, Multinational Corporations such as Dole, Chiquita Brands International and United

Fruit (Chapman, 2007; Kopel, 2008). This singular focus on Cavendish bananas creates

niche market potential for non-Cavendish bananas seldom exploited. There is precedence

for the sale of other banana varieties on the market. In the 1880’s, for example, U.S.

banana markets consisted of a number of cultivars other than ‘Gros Michel’- a former

industry standard replaced due to its susceptibility to Panama Disease - that were

apparently known by name as they were referenced in recipes found in turn-of-the-

century cookbooks and magazines (Danielles andO’Keefe, 2012; Soluri, 2002; Stover

and Simmonds, 1987).

The climate in coastal Alabama is considered subtropical and is relatively mild

compared to other regions and parts of the southeastern US. At the Gulf Coast Research

and Extension Center (GCREC) in Fairhope, Baldwin County, AL (30°31'35.018" North,

87°53'44.473" West) mean monthly maximum and minimum temperatures are within

cardinal temperature ranges for 7 months during the year (Alabama Mesonet data 2008-

2012; Robinson and Galán-Saúco, 2010a) with mean temperatures slightly above range

from mid-June to mid-August (Figure 2. 3.). Cardinal temperatures for banana

47

production fall in the range of 57 °F to 88 °F with optimal range of 72 °F to 88 °F

(Robinson, 1996). For satisfactory growth bananas require 2,000 to 2,500 mm of rainfall

distributed evenly throughout the year which translates into 25 mm per week (Robinson

and Galán-Saúco, 2010a). The GCREC site rests on a Malbis sandy Loam. The region

also experiences a total annual precipitation of approximately 1,600 mm of rainfall the

majority occurring from rain events distributed in the active growing months (March –

November) and reaching 1,252 mm. this translates into 34 mm of rain each week. Rain

events tend to increase from March – August decreasing slightly from September –

November with the area receiving an average of 14.6 mm rain per event.

Health Benefits of Banana Fruit

Fresh bananas provide significant health benefits to consumers. In the US, high

incidences of diet-related chronic diseases such as cancer, stroke, hypertension and heart

disease persist. Increasing fruit consumption is a strategy of increasing consumption of

phenolics and antioxidants which work to counter the damaging and disease-causing

effects of free radicals that are generated during normal chemical processes occurring

within the human body (CDC, 2013). Current USDA guidelines suggest that fruits and

vegetables should make up 50% of meals consumed because of their content of bioactive

compounds (Patil et al., 2014). Consumption of fruit, vegetables and grains as part of a

regular diet can lead to positive health outcomes (Bellavia et al., 2013). In fact, the

World Health Organization (WHO) has promoted the consumption of fruits and

vegetables as a means to reduce diet-related health issues (Goldman, 2014). Bananas are

not only an excellent source of vitamin B6 and contain moderate levels of Vitamin C,

Manganese, and potassium but they are also a suitable source of phenolics and

48

anthocyanins. Total phenolics of Musa Cavendish was found to exist more abundantly in

the peel (907 mg 100 g dry wt. -1) than the pulp (232 mg 100 g dry wt.-1) (Someya et al.,

2002).

Many fruit crops exhibit predictable flowering and fruiting stages that coincide

with particular seasons; however, banana flowering seems to be independent of

temperature and light (Robinson and Human, 1988). The elicitor of floral initiation in

bananas is unknown as bananas flower throughout the season without regard for

temperature or light. Several attempts during the early and mid-20th century were made

to describe origin and development of the banana inflorescence (Fahn, 1953; Simmonds

1959).

Nevertheless, inflorescence is formed without externally evident visual cues. It is

accepted however that flowering has occurs after a banana plant has reached a critical

cumulative leaf surface area that corresponds to the production of 37-46 leaves cycle-1

(Vargas et al., 2008). Flower emergence is said to have occurred when the proximal

floral bract opens to reveal the initial female hand on the hanging banana bunch

(Robinson, 1996) (Figure 2. 4.). Bunch weight can be affected by the season in which

flower emergence takes place. Flowers initiated during periods when temperatures are in

excess of the optimal mean temperature of 22 °C produced bunches of correspondingly

reduced weight (Stover and Simmonds, 1987). Monitoring LER, number of standing

leaves (NSL), and cumulative leaf number (CLN) helps predict fruit production. Abiotic

factors such as temperature, irrigation/rainfall and plant spacing affect LER and rate of

photosynthesis and will ultimately affect flower initiation and time of harvest.

49

However, though bananas have wide adaptability and can tolerate abiotic stresses,

they respond acutely to their environment and sub-optimal conditions will manifest slow

growth, delayed fruit production, reduced quality of fruit and ornamental appeal (Fonsah

et al., 2004; Robinson, 1996; Surendar et al., 2013; Zhang et al., 2011). Drastic shifts in

environmental conditions such as temperature and rainfall occur regularly in the

subtropics and this will impose several constraints on banana markets. Several areas of

concern in banana production in the subtropics need to be addressed – the most critical of

which are banana phenological responses to a given geographical area. Phenology of

bananas is even more difficult to study in the subtropics due to wider variations in

temperature than in the tropics so detailed studies become more important where

conditions are variable and extreme (Robinson, 1996). The purpose of this project is to

determine the best suited cultivars for fruit production and landscape potential of cold-

hardy, short-cycled, non-Cavendish bananas in coastal Alabama by evaluating

phenological responses and measuring fruit quality through both physiochemical and

pomological analyses.

Materials and Methods

Thirteen banana cultivars derived from tissue culture were supplied by Agri-Starts

Whole Sale Nursery (Apopka, FL). The cultivars are as follows: ‘Gold Finger’ (AAAB),

‘Saba’ (ABB), ‘Dwarf Cavendish’ (AAA), ‘Pisang Ceylon’ (AAB), ‘Double’ (AAA),

‘Dwarf Green’ (AAA), ‘Dwarf Red’(AAA), ‘Raja Puri’(AAB), ‘Grand Naine’(AAA),

‘Cardaba’(ABB), ‘Viente Cohol’(AA), ‘Sweet Heart’(AABB), and ‘Ice Cream’(ABB).

Banana plants were at the 3 to 8 leaf stage upon shipment and were potted in 8-inch

containers on 12 April 2013 using Promix plant media (Premier Tech Horticulture,

50

Quakertown, PA). Bananas received a top dress of 15 g of Osmocote 14-14-14 on April

12. Bananas received an additional 100 ml of 20-10-20 at a concentration of 250 ppm

week-1 beginning April 22.

Bananas were planted at the Gulf Coast Research and Extension Center in

Fairhope, AL, USA (30°31'35.018" North, 87°53'44.473" West) on June 6, 2013 after

pseudostem length reach a minimum of 61 cm on a Malbis sandy loam (Figure 2. 5.).

Bananas were separated by height class: Dwarf (1.5 m -2.5 m); Medium (2.5 m- 4.2 m);

and Tall (3.6 m – 7.6 m) and followed an experimental design that consisted of six single-

plant replications arranged in a completely randomized design (CRD) with cultivar and

days-from-planting (DFP) in a factorial arrangement in 2013. The region of the gulf coast

of Alabama experienced uncharacteristic and extremely low temperatures in late

December, 2013 and early January 2014 (Figure 2. 6.) Absolute low temperature in the

field reached -10 °C. The PC crop succumbed to the low temperatures; however,

rhizomes of the PC crop survived and ratoon plants (suckers) were successfully generated

from the lateral meristems of the rhizomes and resulted in vigorous plants for the

following season (Fig 2. 7.).

In 2014 phenological data was measured from days from mature leaf (DFM) in

place of DFP. Mature leaf or F10 leaf indicates transition from juvenile stage to

vegetative stage and is characterized as having a width at the widest expanse of 10 cm or

greater. This occurred on 18 March 2014. Bananas were planted on raised beds 0.9 m

and 0.3 m high. Irrigation was supplied through drip tubing (Irrigation Mart, Rushton,

LA) that had an emitter spacing of 61 cm. Bananas received irrigation at a rate of 50 mm

week-1. Bananas were planted at an in-row spacing of 2.4 m and a 3 m spacing between

51

rows. Weeds were controlled by application of Finale® herbicide (Bayer Environmental

Sciences, Research Triangle Park, NC) at a rate of (118 ml·L-1·ha-1) at 2 application

month-1.

Lateral meristems were allowed to persist on the corm which necessitated

monthly management of suckers. Pseudostems of suckers were cut at soil level and were

covered with soil to prevent microbial invasion (Fonsah and Chidebelu, 1995;

Robinson and Gálan-Saúco, 2010b).

Phenological data collection consisted of leaf emergence rate (LER), pseudostem

height as measured from the ground to the bifurcation formed by the petiole bases of the

top two leaves, pseudostem circumference taken at 30 cm, of pseudostem at flowering,

DFM to flower emergence (exposure of first flower set of the inflorescence), number of

suckers produced, laminal length and width of the third positioned leaf, leaf area index

(LAI), number of standing leaves (NSL), ambient and soil temperatures, cumulative leaf

production (CLP) . Watchdog dataloggers (Spectrum Technologies, Aurora, IL) were

installed on both exterior rows and a center row to measure ambient and soil temperature.

Dataloggers were placed at opposing ends of a row as well as at row center. Dataloggers

were programed to collect ambient and soil temperature at 30- minute intervals.

Statistics

Data was analyzed using SAS statistical analysis program (Cary, NC). Anova was

performed on all growth parameter responses using PROC GLIMMIX. Data were

analyzed separately for each year and cultivar size group combination. The experimental

design was a completely randomized design (CRD) with a factorial arrangement of

cultivars and DFP or DFM. Non-normal counts were analyzed using either the Poisson

52

or negative binomial distribution. Differences among cultivars were determined using

Shaffer Simulated method or T-test.

Results and Discussion

Dwarf cultivars were represented by triploid banana plants of the species

acuminata (AAA) and all belonged to the Cavendish subgroup therefore there was very

little genetic variability (Figure 2. 8.). However, phenological differences were found. In

2013, there was no interaction between the main effects DFP and cultivar in pseudostem

height (Table 2. 1. and 2.2). The pseudostem of ‘Dwarf Red was significantly taller than

‘Dwarf Cavendish’ and ‘Double’ with mean pseudostem lengths of 103.6 cm, 85.4 cm,

and 85.3 cm respectively. Pseudostems increased over 100% between 34 DFP and 59

DFP and by 62% between 59 DFP and 95 DFP. Pseudostem height increases were less

dramatic as temperatures became cooler resulting in an increase of only 8% between 124

DFP and 150 DFP.

There was a significant interaction between DFP and cultivar in pseudostem

circumference (Table 2. 3.). Of the five dwarf cultivars ‘Dwarf Cavendish’ followed a

significant linear trend between 34 DFP and 150 DFP while the remaining four cultivars

followed a quadratic trend. Differences were found among cultivars at 124 DFP and 150

DFP. Pseudostem circumference of ‘Dwarf Red’ was significantly larger than ‘Dwarf

Cavendish’ and ‘Grand Nain’ at 50 cm, 42 cm and 40.2 cm respectively at 124 DFP.

These differences between ‘Dwarf Red’ and the remaining cultivars expanded to include

all with the exception of ‘Dwarf Green’. There were no significant differences in the

main effects in the HCR which followed a quadratic trend between 34 DFP and 150 DFP

(Table 2.4.).

53

In NSL, ‘Dwarf Red’ was able to sustain significantly fewer leaves (10.8) than

‘Dwarf Cavendish’ (12.2), ‘Double’ (12.8), and ‘Grand Nain’ (12.3) throughout the

growing season (Table 2. 5.). Mean NSL increased by approximately one leaf at four of

the five samplings. This suggests that leaf emergence was approximately equal to leaf

total senescence.

There was a difference between the main effects of cultivar and DFP in 2013

(Table 2. 6.). Laminal length of ‘Dwarf Red’, and ‘Grand Nain’ followed a significant

linear trend while ‘Dwarf Cavendish’, ‘Dwarf Green’ and ‘Grand Nain’ followed a

quadratic trend. The largest increase was 91% which occurred between 59 DFP and 94

DFP in ‘Grand Nain.

Laminal width does not change considerably relative to length. Therefore there

were few differences demonstrated (Table 2. 6.). Laminal width of ‘Dwarf Cavendish’,

‘Dwarf Red’ and ‘Double’ followed a linear trend while ‘Dwarf Green’ followed a

quadratic trend. Few differences were found at 124 DFP and 150 DFP. Width of ‘Dwarf

Red’ was significantly larger than ‘Double’ at 124 DFP. This difference expanded to

include the remainder of the cultivars by 150 DFP. Lamina exhibited characteristic

shredding in response to high winds (Figure 2. 9.).

Leaf area index (LAI) was significantly affected by the main effects cultivar and

DFP (Table 2. 7.). LAI increased linearly from 34 to 150 DFP in ‘Dwarf Red’ and

‘Double’ but followed a quadratic trend in the remaining cultivars. Differences were

found among cultivars at 124 DFP and 150 DFP. There was a difference between ‘Dwarf

Red’ (1.59) and ‘Double’ (0.83) at 124 DFP so was theoretically able to intercept more

54

light radiation. By the end of the season ‘Dwarf Red’ had also had a greater potential

than ‘Dwarf Cavendish’ and ‘Grand Nain’ to intercept light radiation.

Phyllochron, as measured by LER, ranged from 5 leaves to 1 leaf month-1 when

temperatures were cooler (Table 2. 8.). This led to a mean total leaf number that ranged

from 18-35 leaves. There was a significant interaction between the main effects once

again. ‘Dwarf Cavendish’ produced significantly more leaves during the season than

‘Dwarf Green’ and ‘Dwarf Red’ (Table 2. 9.).

Contrary to results found in 2013 where the interaction between cultivar and DFP

were not significant, there was a significant interaction between cultivar and DFM in both

pseudostem length and pseudostem circumference in 2014 (Table 2. 10.). Both followed

a linear trend. Data were collected on 60, 90, 117, 160, 185, and 208 DFM. HCR

increased linearly from 60 DFM to 208 DFM (Table 2. 11.).

There was not an interaction between DFP and cultivar in NSL (Table 2. 12.). All

cultivars were able to sustain a significantly higher number of leaves than ‘Dwarf Red’ in

2014 with the exception of ‘Dwarf Green’. The mean number of leaves sustained by

dwarf cultivars ranged from 5 at 60 DFM to 14 at 208 DFM.

There was no interaction between DFM and cultivar in laminal length (table 2.

13.). The largest increase in mean laminal length in all cultivars was 67% which occurred

between 60 and 90 DFP. There was an interaction between DFM and cultivar in Laminal

width. Each cultivar demonstrated a linear increase in laminal width. Differences among

cultivars did not occur until 185 DFM and 208 DFM. LAI increased in quadratic fashion

and it ranged from a mean of 0.03 to 1.61 indicating that the ability to intercept light

increased (Table 2. 14.).

55

As in 2013, the interaction between DFM and cultivar was not significant in LER.

The phyllochron increased from 4 to 6 leaves between 60 DFM to 160 DFM. ‘Double’

and ‘Dwarf Cavendish’ followed a quadratic trend while ‘Dwarf Green’, Dwarf Red’ and

‘Grand Nain’ followed a linear trend in CLN (Table 2. 15.). ‘Dwarf Green’ and ‘Dwarf

Red’ produced significantly fewer leaves than all other cultivars by the end of the season.

Phenological data was collected periodically from initiation of the vegetative

stage in banana which as indicated by the production of the F10 leaf (Robinson and Galán

Saúco, 2010c) which measures at the widest point at 10 cm or greater. Banana reached

this stage on approximately 18 March 2014. Phenological data were collected 60, 117,

160, 185, and 208 d from the production of the first mature leaf (DFM).

Pseudostem length was affected by an interaction between cultivar and DFM

(Table 2. 16.). The cultivars ‘Cardaba’ and ‘Gold Finger’ followed a linear trend while

‘Raja Puri’ and ‘Ice Cream’ followed a quadratic trend. At each DFM ‘Cardaba’

consistently had the tallest pseudostems but were similar to ‘Raja Puri’ and ‘Ice Cream’

at 60 DFM and similar only to ‘Ice Cream’ at 90 DFM and at each sampling thereafter.

‘Gold Finger’ produced the shortest pseudostems which were similar only to ‘Raja Puri’

at each DFM. Pseudostem circumference was also affected by an interaction between

cultivar and DFM. Consistent with findings in pseudostem length, ‘Caradaba’ and ‘Ice

Cream’ exhibited significantly longer circumferences at most samplings throughout the

season.

HCR was not significant during mid-season (117 DFM) or late season (208 DFM)

(Table 2. 17.). Most cultivars followed a linear trend with the exception of ‘Ice Cream’

which followed a quadratic trend. ‘Gold Finger’ produced the lowest HCR which

56

indicated a stronger pseudostem; however, HCR of “Gold Finger’ was similar to those of

‘Ice Cream’ and ‘Raja Puri’ late in the season.

Cultivars were able to support a similar number of leaves (NSL) at each DFM.

All cultivars followed a quadratic trend as NSL increased at each sampling (Table 2. 18.).

Leaves of ‘Gold Finger’ were the smallest as indicated by laminal length and width

(Table 2. 19. and 2. 20.). LAI was affected by an interaction between cultivar and DFM

and each cultivar followed a linear trend (Table 2. 21.). LAI of ‘Cardaba’ and ‘Ice

Cream’ were consistently larger numerically at each sampling and could theoretically

intercept more light but LAI of ‘Cardaba’ was statistically similar to most other cultivars

throughout the season.

A sufficient number of leaves emerged (Table 2. 22.) at each DFM during the

warmer months and decreased as temperatures became cooler. There was an interaction

between cultivar and DFM in CLN and all followed a quadratic trend (Table 2. 23.).

‘Raja Puri’ produced the fewest leaves at each sampling.

In 2013, pseudostem length of ‘Saba bananas was statistically higher than both

‘Pisang Ceylon’ and ‘Sweetheart’ for most of the season (Table 2. 24.). Pseudostem

circumference of ‘Pisang Ceylon’ bananas was statistically smaller than ‘Saba’ and

‘Sweetheart’ at each DFM. This translated to a statistically higher HCR for ‘Pisang

Ceylon’ indicating a weaker pseudostem (Table 2. 25.).

‘Saba’ bananas were able to support a larger number of leaves during the latter

half of the season (Table 2. 26.) and exhibited lamina that were statistically of greater

length and width than ‘Pisang Ceylon’ and ‘Sweetheart’ for much of the season (Table 2.

27.). Surprisingly, LAI was not significant until 208 DFM (Table 2. 28.). ‘Pisang Ceylon’

57

had the fewest leaves to emerge (Table 2. 29.) than ‘Saba’ and ‘Sweetheart’ but CLN was

similar to ‘Saba’ and statistically smaller than ‘Sweetheart (Table 2. 30.).

In 2014, the pseudostem of ‘Saba’ was statistically taller longer than both ‘Pisang

Ceylon’ and ‘Sweetheart’ at each DFM (Table 2. 31.). Both ‘Saba’ and ‘Sweetheart’

followed a linear trend while ‘Pisang Ceylon’ followed a quadratic trend. Pseudostem

circumference of ‘Saba’ bananas was statistically the largest. Pseudostem circumference

of ‘Pisang Ceylon’ and ‘Sweetheart’ were similar until 160 DFM (Table 2. 31.).

Thereafter, circumference of ‘Pisang Ceylon’ pseudostems were the smallest statistically.

Smaller circumferences of ‘Pisang Ceylon’ pseudostems resulted in higher HCR and

were theoretically more vulnerable to lodging. By the end of the season pseudostems of

‘Sweetheart’ bananas were strongest statistically and less prone to lodging due to high

winds or heavy crop load (Table 2. 32.).

Tall bananas were able to support fewer leaves after mid-season as NSL

decreased after this point (Table 2. 33.). ‘Saba’ produced the leaves in the largest surface

areas of the tall banana as laminal length and width of ‘Saba’ statistically higher than

those of ‘Pisang Ceylon’ and ‘Sweetheart’ at each DFM (Table 2. 34. And 2.35.). As

expected due to comparatively larger leaf surface area, ‘Saba’ bananas were theoretically

able to intercept more light radiation than ‘Pisang Ceylon’ and ‘Sweetheart’ as indicated

by LAI (Table 2. 36.).

Floral initiation, yield, and bunch characteristics of the R3 crop

Sporadic flowering occurred in October, 2014 which did not allow sufficient time

for bunch development nor efficient representation from cultivars for statistical analysis.

In 2015 in the R3 crop flower emergence began on 28 July. Morphological and

58

phenological characteristics were determined at the time of flower emergence (Table 2.

37.). Among the dwarf bananas, flower emergence occurred in two of the five cultivars –

‘Double’ and ‘Grand Nain’. At the time of flower emergence ‘Double supported a

significantly higher number of leaves than ‘Grand Nain’ but both cultivars had a

sufficient number of leaves to carry the developing bunch to maturity (Table 2. 38.).

Pseudostem length of ‘Double’ was 156.64 cm while ‘Grand Nain’ pseudostems were

149.81 cm. There were no statistical differences found between these two cultivars.

Pseudostem length of ‘Grand Nain’ cultivated in the subtropics of the Canary Islands was

58% taller than pseudostems of ‘Grand Nain’ bananas in the current study comparing

plants of the same ratoon. ‘Grand Nain’ bananas in the current study were 41% taller

than bananas cultivated in the subtropical region of coastal Georgia, USA (Savannah)

which is in the same USDA hardiness zone (Galán-Saúco et al., 1992; Krewer et al.,

2008).

Both cultivars produces leaves well below the 38-50 leaves expected prior to

flower emergence – 26.2 and 24.4 leaves plant-1 for ‘Double’ (Figure 2. 10.) and ‘Grand

Nain’ (Figure 2. 11.) respectively. Flower emergence occurred 15 d earlier in ‘Double

(160) than in ‘Grand Nain’ (175). Bunch weight of ‘Double’ bananas was significantly

higher (11.86 kg) than ‘Grand Nain’ (5.76 kg). Bunches of ‘Grand Nain’ bananas

cultivated in the Canary Islands were 35 kg on average from 1993 and 1994 production

seasons (Cabrera et al., 1998). The number of hands per bunch was similar for ‘Double’

and ‘Grand Nain’, 8.7 and 8.3 respectively. Hand number of both cultivars was

decidedly lower in the current study than in bananas cultivated in the Canary Islands (12

hands bunch-1).

59

Among the medium height bananas all four of the remaining cultivars reached

flower emergence. At flower emergence, ‘Ice Cream’ and ‘Cardaba’ retained

approximately 13 leaves which was significantly higher than the number of leaves

retained by ‘Gold Finger’ and ‘RajaPuri’ at 9.2 and 8.8 leaves respectively. Pseudostem

length of ‘Ice Cream’ and ‘Cardaba’ at flower emergence differed significantly from

‘Gold Finger’ but was similar to ‘Raja Puri’. ‘Cardaba’ and ‘Raja Puri’ produced

significantly fewer leaves than ‘Ice Cream’ but produced a CLN similar to ‘Gold Finger’.

Flower emergence occurred earliest in ‘Cardaba’ which was similar to ‘Gold Finger’ (145

d and 166 d respectively). ‘Ice Cream’ and ‘Raja Puri’ required 58-79 d longer than

‘Cardaba’ for flower emergence to occur. Of the four remaining medium height banana

cultivars flower emergence occurred in ‘Gold Finger’ and ‘Cardaba’ such that there was

sufficient for bunches to ripen before early frost. Bunch weight of ‘Cardaba’ (7.22 kg)

(Figure 2. 12.) was numerically higher than the bunch weight of ‘Gold Finger’ (Figure 2.

13.). ‘Gold Finger’ and ‘Ice Cream’ demonstrated a significantly higher number of hands

bunch-1 than ‘Cardaba’ and ‘Raja Puri’.

Of the three tall cultivars, flower emergence occurred in ‘Sweetheart’ and ‘Pisang

Ceylon’ but not in ’Saba’. ‘Sweetheart’ (Figure 2. 14.) was the only cultivar to produce

mature bunches prior to early frost; however, bunch characteristics of ‘Pisang Ceylon’

and ‘Sweetheart were compared and there were no significant difference found in number

of hands bunch-1, total finger number bunch-1 or finger number hand-1.

Survivability

Dwarf bananas experienced the most plant mortality in comparison to the other

types (Table 2. 39.). Between the parent crop (PC) and R1 in 2013 and 2014, 83% of

60

‘Grand Nain’ mats survived while only 50% ‘Dwarf Red’ bananas survived. By the end

of 2015, ‘Dwarf Green’ maintained 100% survival. Bananas of the Cavendish subgroup

have 100% of their genome derived from Musa acuminata, therefore clones of this type

tend to be less cold hardy and succumb to low temperatures. It is not surprising that most

of the mortality was demonstrated among the dwarf bananas since they were all members

of the Cavendish subgroup. Among medium height bananas, low survivability was

demonstrated in ‘Veinte Cohol’. Similarly, the genome of ‘Veinte Cohol’ is 100%

derived from Musa acuminata. Additionally, ‘Veinte Cohol’ is diploid which are known

to be less cold hardy than bananas with higher ploidy.

Conclusions

Dwarf banana cultivars responded similarly in phenology to the conditions of the

gulf coast of Alabama. This is the result of a lack of genetic variability considering all of

the selected dwarf cultivars belong to the Cavendish subgroup and as characteristic of

this group, they were all triploid and 100% acuminate which makes them cold sensitive.

Moreover, cultivars ‘Dwarf Red’, ‘Dwarf Green’ and ‘Double’ are sports of ‘Dwarf

Cavendish’ (Personal communication). The most important cultivars of this group are

‘Dwarf Cavendish’ and ‘Grand Nain’ because of the reliance of Multinational companies

on these two Cavendish varieties. The variety ‘Dwarf Green’ had the highest survival

rate (100%); however, this variety is considered a banana for home cultivation and has

not be considered as suited for commercial production.

Medium height bananas selected for this study demonstrated the most diversity

and the most potential as components of a banana niche market for coastal Alabama.

‘Cardaba’ and ‘Ice Cream’ were the most vigorous in terms of pseudostem length and

61

circumference and the number of leaves the plants were able to maintain. All medium

height bananas flowered, but only two of the five medium height cultivars developed

mature bunches before the early frost. ‘Gold Finger’ was not considered the most

vigorous banana in this study but this cultivar along with ‘Cardaba’ was able to produce

mature bunches during in both the R1 crop (data not shown) and the R2 crop.

Of the tall bananas, floral initiation occurred in ‘Sweetheart’ and mature bunches

were produced by the end of the season. ‘Pisang Ceylon’ flowered later in the season and

as a consequence, did not produce mature bunches, while ‘Saba’ did not flower in this

study.

Diseases such as tropical race 4 Panama Disease (TR4) and black Sigatoka are

considered among the most economically important in the industry. The cultivar ‘Gold

Finger’ and ‘Sweetheart’ are reported to have resistance to these two diseases. Moreover,

they are tetraploids and as a result have more tolerance to cold than cultivars of lower

ploidy levels. These qualities along with a demonstrated reliability in fruit set in this

study may lead to their selection in Alabama niche market.

Conversely, ‘Veinte Cohol’ is a diploid plant (AA) and is cold sensitive. It was

noted by the end of the PC crop (2013) floral initiation had occurred in all ‘Veinte Cohol’

bananas. This observation was made when pseudostems damaged by the severe winter of

2013-14 were cut and removed from the field. When pseudostems of ‘Veinte Cohol’

were cut creating a cross section of the pseudostem, the “true stem” which bares the

inflorescence was discovered which confirmed floral ignition had taken place. Moreover

the only surviving ‘Veinte Cohol’ plant in the study flowered during the R2 crop and

produced a mature bunch before fall.

62

‘Veinte Cohol’ is known in the industry to have a short production cycle. Some

banana producing regions use an annual planting system where ‘Veinte Cohol’ is planted

and is able to flower in a single season reliably. The banana mats are removed and the

field is replanted with ‘Veinte Cohol’ the following season. Additionally, ‘Veinte Cohol’

could be used in protective horticulture such high tunnels or greenhouses.

Results to date show promise for banana niche mark in coastal Alabama;

however, when phenology and physiology of bananas used in this study are compared

with those of the same cultivars produced in other subtropical regions, plant vigor and

yield are notably lower in bananas produced in coastal Alabama. Reduced vigor may

cause a delay in floral imitation and a corresponding reduction in yield. More

phenological studies are necessary to arrive at a more precise determination in the

selected banana cultivars adaptability to the region and reliability as a source of bananas

for a new and developing banana niche market.

63

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67

Table 2. 1 P-values of interaction terms of dwarf, medium, and tall banana cultivars

Variable Cultivar* DFPz 2013 Cultivar*DFMy 2014 Dwarf Pseudostem Height (cm) 0.1672 0.1271 Pseudostem Circumference (cm) 0.0042 0.5778 Height: Circumference Ratio 0.6210 0.8012 Number of Standing Leaves (NSL) 0.3575 0.4515 Cumulative Leaf Number (CLN) 0.9999 0.0020 Leaf Area Index (LAI) 0.9999 0.9998 Leaf Emergence Rate (LER) 0.2348 0.0020 Medium Pseudostem Height (cm) <0.0001 0.0042 Pseudostem Circumference (cm) <0.0001 0.0130 Height: Circumference Ratio 0.2738 0.2386 Number of Standing Leaves (NSL) 0.0027 0.0004 Cumulative Leaf Number (CLN) 0.0308 <0.0001 Leaf Area Index (LAI) 0.0021 0.0088 Leaf Emergence Rate (LER) 0.2348 0.0020 Tall Pseudostem Height (cm) <0.0001 <0.0001 Pseudostem Circumference (cm) <0.0001 <0.0001 Height: Circumference Ratio 0.2321 <0.0001 Number of Standing Leaves (NSL) 0.0020 0.0283 Cumulative Leaf Number (CLN) 0.0014 0.9688 Leaf Area Index (LAI) <0.0001 <0.0001 Leaf Emergence Rate (LER) 0.8731 0.9949 zDFP = Days from planting. Used as a variable in 2013 yDFM = Days from mature leaf used as a variable in 2014

68

Table 2. 2. Pseudostem length (cm) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast Rec, Fairhope, AL – parent crop 2013. Pseudostem Pseudostem Cultivarz Height (cm) DFPz Height (cm) Dwarf Cavendish 85.4 by 34 30.5 Dwarf Green 94.5 ab 59 64.0 Dwarf Red 103.6 a 95 103.6 Double 85.3 b 125 125.0 Grand Nain 88.4 ab 150 131.0 Sign. x Q*** zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

69

Table 2. 3. Pseudostem circumference (cm) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Cultivarz Days from Plantingz 34 59 95 124 150 Sign.x D. Cavendish 14.6 ns 22.0 ns 30.6 ns 41.2 by 42.1 bc L*** Dwarf Green 13.4 24.8 35.4 46.0 ab 46.0 ab Q*** Dwarf Red 14.3 25.8 36.4 50.0 a 50.0 a Q** Double 13.4 22.0 32.5 39.2 ab 40.2 c Q** Grand Nain 12.6 24.0 30.6 42.1 c 40.2 c Q**

zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

70

Table 2. 4. Height: circumference ratio of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Days from Plantingz

34 59 95 124 150 Sign.y HCR 2.2 2.7 3.2 2.9 3.0 Q*** zThe DFP main effect was significant. yIndicates a significant quadratic effect

71

Table 2. 5. Pseudostem circumference (cm) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Cultivarz NLP DFPz NLP Dwarf Cavendish 12.2 ay 0 10.1 Dwarf Green 10.8 b 30 11.8 Dwarf Red 10.7 b 66 12.4 Double 12.8 a 95 13.2 Grand Nain 12.3 a 121 11.4 Significancex Q*** zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

72

Table 2. 6. Length and width (cm) of the third-position lamina of dwarf(Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. DFPz 34 59 95 124 150 Sign.x Cultivarz Length (cm) Dwarf Cavendish 41.1 ab 65.0 bc 112.5 ns 127.7 aby 125.4 bc Q*** Dwarf Green 41.4 a 75.2 a 125.7 122.6 ab 126.2 ab Q** Dwarf Red 42.2 a 76.2 ab 115.0 135.3 a 149.4 a L*** Double 40.1 b 66.3 c 100.0 104.0 b 117.8 c L*** Grand Nain 38.1 b 65.5 c 125.0 117.0 b 120.7 c Q***

Width (cm)

Dwarf Cavendish 21.0 ns 34.0 ns 52.5 ns 62.2 ab 63.0 b L** Dwarf Green 23.1 43.1 64.5 67.0 ab 72.6 b Q*** Dwarf Red 24.3 41.4 56.6 81.2 a 78.2 a L*** Double 18.3 31.0 48.5 50.3 b 58.4 b L*** Grand Nain 17.7 31.75 58.6 53.3 ab 56.4 b Q*** zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

73

Table 2. 7. Leaf area index (LAI) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. DFPz Cultivarz 34 59 95 124 150 Sign.x Dwarf Cavendish 0.11 ns 0.28 ns 0.84 ns 1.32 aby 1.00 c Q** Dwarf Green 0.10 0.42 0.97 1.07 ab 1.08 ab Q** Dwarf Red 0.10 0.37 0.88 1.59 a 1.43 a L*** Double 0.09 0.30 0.73 0.83 b 1.02 bc L*** Grand Nain 0.08 0.30 1.11 0.97 ab 0.86 c Q*** zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

74

Table 2. 8. Leaf emergence rate (LER) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – Parent Crop 2013. DFPz

34 59 95 124 150 Sign.y LER 5 6 6 4 1 Q*** zThe DFP main effects were significant yIndicates a significant quadratic effect

75

Table 2. 9. Cumulative leaf number (CLN) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Cultivarz TLN DFPz TLN Dwarf Cavendish 30 ay 34 18 Dwarf Green 26 b 59 24 Dwarf Red 26 b 95 30 Double 29 ab 124 34 Grand Nain 28 ab 150 35 Sign.x Q***

zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

76

Table 2. 10. Pseudostem length and circumference at each sampling period of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL, R1 crop, 2014. DFPz

60 90 117 160 185 208 Sign.y Length (cm) 24.4 48.7 76.2 91.4 140.2 158 L** Circumference (cm) 11.5 19.1 26.0 32.5 46.0 47.0 L*** zThe DFP main effects were significant yIndicates a significant linear effect

77

Table 2. 11. Mean height:circumference at each sampling period of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz

60 90 117 160 185 208 Sign.y HCR 2.1 2.6 3.0 3.0 3.1 3.4 L*** zThe DFP main effects were significant yIndicates a significant linear effect

78

Table 2. 12. Mean number of standing leaves (NSL) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. Cultivarz NSL DFPz NSL Dwarf Cavendish 11 ay 60 5 Dwarf Green 10 ab 90 7 Dwarf Red 9 b 117 10 Double 11 a 160 11 Grand Nain 1 1a 185 14 208 14 Sign.x L*** zThe Cultivar and DFP main effects were significant yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant linear effect

79

Table 2. 13. Mean laminal length and width at each sampling of dwarf (Musa AAA (Cavendish Subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPzy

60 90 117 160 185 208 Sign.w Length (cm) 30.0 48.5 81.0 112.3 131.0 143.0 L***

Width (cm)

Cultivary Dwarf Cavendish 17.5 ns 25.6 ns 43.2 ns 66.8 ns 65.0 abx 70.4 ab L*** Dwarf Green 18.0.1 26.1 44.5 47.7 69.0 ab 73.0 ab L*** Dwarf Red 18.2 27.1 67.0 58.6 76.2 a 81.5 a L*** Double 15.4 26.4 48.0 51.5 58.7 b 60.0 b L*** Grand Nain 15.7 24.4 58.6 55.3 64.7 ab 68.0 ab L*** zThe DFP main effect was significant (length). yThe Cultivar and DFP main effects were significant (width) xAny two means within a row not followed by the same letter are significantly different at P< 0.05. wIndicates a significant linear effect

80

Table 2. 14. Leaf area index (LAI) and LER each sampling of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz

60 90 117 160 185 208 Sign.y

LAI 0.03 0.12 0.41 0.86 1.34 1.61 Q*** LER 4 5 5 6 4 2 Q**

zThe DFP main effect was significant (LAI and LER) yIndicates a significant quadratic effect

81

Table 2. 15. Cumulative leaf number (CLN) of dwarf (Musa AAA (Cavendish subgroup)) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 60 90 117 160 185 208 Sign.x Dwarf Cavendish 5 ns 11 ay 16 a 22 a 26 a 29 a Q** Dwar Green 4 8 ab 13 ab 18 ab 22 b 24 b L*** Dwarf Red 3 8 ab 12 b 15 b 21 b 23 b L*** Double 5 11 a 16 a 22 a 26 a 29 a Q*** Grand Nain 5 9 ab 15 a 21 a 26 a 28 a L*** zThe Cultivar and DFP main effects were significant (width) yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

82

Table 2. 16. Pseudostem length (cm) and circumference (cm) of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014.

DFPz 60 90 117 160 185 208 Sign.x

Length (cm) Cultivarz Cardaba 67.1 ay 115.8 a 177 a 204.2 a 274.3 a 287.0 a L*** Gold Finger 45.7 b 70. 1b 122 b 146.3 c 195.1 b 204.2 c L*** Ice Cream 70.1 a 119.0 a 174 a 195.0 ab 253.0 a 256.0 ab Q** Raja Puri 52.0 ab 88.4 b 143.2 b 170.6 bc 204.2 b 213.4 bc Q**

Circumference (cm) Cardaba 20.1 ns 36.4 a 50.0 a 60.3 a 68.0 a 71.7 a Q*** Gold Finger 16.3 30.0 ab 37.3 b 51.0 b 59.3 b 60.2 ab L*** Ice Cream 19.1 35.4 a 53.0 a 65.1 a 74.0 a 72.7 a Q*** Raja Puri 16.3 27.0 b 40.2 b 47.0 b 56.4 b 55.5 b Q*** zThe Cultivar by DFP interaction was significant (Length and Circumference). yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

83

Table 2.17. Height:circumference ratio of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014.

DFPz Cultivarz 60 90 117 160 185 208 Sign.x Cardaba 3.3 ay 3.2 a 3.6 ns 3.4 a 4.1 a 4.0 ns L** Gold Finger 2.7 b 2.4 b 3.2 2.9 b 3.3 b 3.3 L** Ice Cream 3.4 a 3.4 a 3.3 3.0 b 3.4 b 3.6 Q* Raja Puri 3.3 a 3.3 a 3.6 3.6 a 3.6 ab 3.8 L* The Cultivar by DFP interaction was significant. zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

84

Table 2. 18. Number of standing leaves of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014.

DFPz Cultivarz 60 90 117 160 185 208 Sign.y Cardaba 5 9 11 15 16 16 Q*** Gold Finger 6 9 12 14 14 15 Q*** Ice Cream 4 9 10 15 16 16 Q** Raja Puri 5 8 10 12 12 12 Q*** zThe Cultivar by DFP interaction was significant. yIndicates a significant quadratic effect

85

Table 2. 19. Laminal length of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. Cultivarz Length(cm) DFPz Length(cm) Cordaba 141.2ay 60 57.6 Gold Finger 114.0b 90 85.5 Ice Cream 140.4a 117 129.5 Raja Puri 133.0a 160 161.5 185 177.0 208 182.0 Sign.x Q*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

86

Table 2. 20. Laminal width of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. Cultivarz Width (cm) DFPz Width (cm) Cardaba 58.2ay 60 28.4 Gold Finger 48.7c 90 41.0 Ice Cream 54.6ab 117 54.6 Raja Puri 50.8bc 160 62.0 185 64.0 208 68.5 Sign.x Q*** The Cultivar and DFP main effects were significant zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

87

Table 2. 21. Leaf area index (LAI) of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 60 90 117 160 185 208 Sign.x Cardaba 0.13 ay 0.45 a 1.10 ns 1.78 ns 2.23 a 2.41 a L*** Gold Finger 0.07 b 0.23 b 0.76 1.26 1.61 ab 1.80 ab L*** Ice Cream 0.09 ab 0.41 a 0.89 1.84 2.17 a 2.41 a L*** Raja Puri 0.08 ab 0.32 ab 0.74 1.41 1.46 b 1.57 b L*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant linear effect

88

Table 2. 22. Leaf Emergence Rate (LER) of Medium Height non-Cavendish (Musa sp.) Bananas Cultivated at the Gulf Coast REC, Fairhope, AL – R1 Crop 2014.

DFPz 60 90 117 160 185 208 Sign.x

LER 5 5 5 6 3 2 Q** zThe DFP interaction was significant. xIndicates a significant quadratic effect

89

Table 2. 23. Cumulative leaf number (CLN) of medium height non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014.

DFPz Cultivarz 60 90 117 160 185 208 Sign.x Cardaba 5 ns 9 ns 15 ay 21 a 24 a 26 a Q*** Gold Finger 6 10 15 a 22 a 26 a 28 a Q*** Ice Cream 4 9 15 a 22 a 26 a 27 a Q*** Raja Puri 5 9 14 b 19 b 21 b 23 b Q*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

90

Table 2. 24. Pseudostem length and circumference of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. DFPz Cultivarz 34 59 95 124 150 Sign.x

Length (cm) Pisang Ceylon 36.5 ns 76.2 by 131.0 c 164.5 c 173.7 Q*** Saba 40.0 97.5 a 168.0 a 207.2 a 222.5 Q*** Sweetheart 43.0 88.3 b 146.0 b 183.0 b 189.0 Q***

Circumference (cm) Pisang Ceylon 12.4 b 23.0 b 34.4 c 45.0 b 46.0 b Q*** Saba 18.2 a 32.5 a 49.0 a 64.1 a 66.0 a Q*** Sweetheart 17.2 a 30.0 a 45.0 b 61.2 a 62.2 a Q*** zThe Cultivar by DFP interaction was significant (Length and Circumference). yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

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Table 2. 25. Height: circumference ratio of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Cultivarz HCR DFPz HCR Pisang Ceylon 3.5a 34 2.5 Saba 3.1b 59 3.2 Sweetheart 3.0b 95 3.5 124 3.3 150 3.4 Sign.x Q*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect.

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Table 2. 26. Number of leaves present of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. DFPz Cultivarz 34 59 95 124 150 Sign.x Pisang Ceylon 8 ns 12 ns 11 by 13 b 12 ab Q** Saba 9 10 13 a 16 a 13 a Q*** Sweetheart 10 11 12 b 14 b 11 b Q***

zThe cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

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Table 2. 27. Laminal length (cm) and width (cm) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Length (cm) DFPz Cultivarz 34 59 95 124 Sign.x Pisang Ceylon 45.2 by 74.0 c 133.6 ns 136.1 b Q*** Saba 55.3 a 94.0 a 126.2 201.4 a L*** Sweetheart 52.0 a 86.0 b 133.0 178.0 a L*** Width (cm) Pisang Ceylon 22.6 b 37.0 b 64.2 ns 67.3 b Q*** Saba 30.0 a 49.0 a 60.0 80.0 a L*** Sweetheart 25.0 b 39.0 b 54.3 64.0 c Q** zThe Cultivar by DFP interaction was significant (length and width). yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

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Table 2. 28. Leaf area index (LAI) of tall non-Cavendish (Musa sp.)bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. DFPz Cultivarz 34 59 95 124 Sign.x Pisang Ceylon 0.09ns 0.36ns 1.02ns 1.21by Q** Saba 0.17 0.48 1.13 2.33a Q** Sweetheart 0.14 0.41 0.96 1.43b L*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

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Table 2. 29. Leaf emergence rate (LER) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. Cultivarz LER DFPz LER Pisang Ceylon 4 cy 34 5 Saba 5 b 59 6 Sweetheart 5 a 95 6 124 4 150 2 Sign.x Q*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

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Table 2. 30. Cumulative leaf number (CLN) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – parent crop 2013. DFPz Cultivarz 34 59 95 124 150 Sign.x Pisang Ceylon 16 by 22 b 27 b 31 b 32 b Q*** Saba 16 b 21 b 28 b 32 b 34 b Q*** Sweetheart 18 a 24 a 31 a 35 a 37 a Q*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

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Table 2. 31. Pseudostem length (cm) and circumference (cm) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 60 90 117 160 185 208 Sign.x

Length (cm) Pisang Ceylon 52.0 by 91.4 b 140.2 b 167.4 b 213.4 b 213.3 b Q** Saba 82.3 a 128.0 a 192.0 a 222.5 a 304.8 a 335.3 a L*** Sweetheart 48.7 b 94.4 b 143.2 b 164.5 b 219.4 b 238.0 b L***

Circumference (cm)

Pisang Ceylon 17.2 b 28.7 b 36.4 b 44.0 c 51.6 c 52.6 c Q** Saba 25.0 a 41.1 a 61.3 a 79.4 a 89.0 a 94.0 a Q*** Sweetheart 17.2 b 32.0 b 45.0 b 61.2 b 71.0 b 80.4 b L*** zThe Cultivar by DFP interaction was significant (Length and cirfumference). yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

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Table 2. 32. Height: circumference ratio of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 60 90 117 160 185 208 Sign.x Pisang Ceylon 3.0 ns 3.2 ns 3.8 ay 3.8 a 4.1 a 4.3 a L*** Saba 3.3 3.1 3.2 b 2.8 b 3.4 b 3.5 b Q*** Sweetheart 2.8 3.0 3.2 b 2.7 b 3.1 c 3.0 c NS zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

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Table 2. 33. Number of standing leaves (NSL) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 60 90 117 160 185 208 Sign.x

Pisang Ceylon 6 ns 9 ns 10 by 14 ns 11 ns 11 ns Q*** Saba 5 8 12 a 15 13 11 Q*** Sweetheart 5 8 11 ab 13 12 13 Q*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

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Table 2. 34. Laminal Length (cm) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 60 29 57 100 125 148 Sign.x Pisang Ceylon 55.1 by 79.0 b 121.0 b 136.4 b 174.4 c 183.0 b L*** Saba 81.3 a 125.0 a 184.4 a 231.1 a 249.4 a 266.0 a L*** Sweetheart 53.0 b 82.0 b 128.0 b 165.6 b 198.2 b 176.2 b L*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant linear effect

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Table 2. 35. Laminal width (cm) of tall non-Cavendish (Musa sp.) Bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. Cultivarz Width(cm) DFPz Width (cm) Pisang Ceylon 56.0 by 0 33.0 Saba 68.0 a 29 46.2 Sweetheart 55.1 b 57 61.0 100 61.2 125 81.0 148 76.0 Sign.x Q***

zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic effect

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Table 2. 36. Leaf area index (LAI) of tall non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R1 crop 2014. DFPz Cultivarz 0 29 57 100 125 148 Sign.x Pisang Ceylon 0.12 aby 0.37 ab 0.80 b 1.11 b 1.75 b 1.57 b L*** Saba 0.19 a 0.63 a 1.86 a 2.75 a 2.88 a 2.76 a Q*** Sweetheart 0.09 b 0.30 b 0.79 b 1.45 b 2.11 b 1.80 b L*** zThe Cultivar by DFP interaction was significant. yAny two means within a row not followed by the same letter are significantly different at P< 0.05. xIndicates a significant quadratic or linear effect

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Table 2. 37. Phenological comparisons at flower emergence (TLN) of dwarf, medium and tall Cavendish and non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R2 crop 2015. Psuedostem Total Days to NLP Height (cm) Leaf # Flower Yield Cultivar at Flowering at Flowering at Flowering Emergence Bunch-1 (kg)

Dwarf Double 10.8 az 156.64 26.2 160 11.86 a Grand Nain 9.75 b 149.81 24.4 175 5.76 b P value 0.5856 0.6226 0.2635 0.0023 0.045

Medium Ice Cream 13 a 308.86 a 28.2 a 223 a 7.22 Cardaba 12.8 a 365.32 b 24.0 b 145 b 5.63 Gold Finger 9.2 b 195.07 c 25.2 ab 166 b . Raja Puri 8.8 b 229.34 cb 22 b 224 a . P value 0.0001 0.0001 0.0021 0.0040 0.6088

Tall Sweetheart 9.5 a 204.22 b 26.6 179 b . Pisang Ceylon 6.8 b 247.90 a 27.5 217 a . P value 0.0132 0.012 0.6236 0.0023 . zAny two means within a row not followed by the same letter are significantly different at P< 0.05.

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Table 2. 38. Comparison of bunch characteristics of dwarf, medium height and tall Cavendish and non-Cavendish (Musa sp.) bananas cultivated at the Gulf Coast REC, Fairhope, AL – R2 crop 2015.

Total Total Fingers Hand Finger Per Cultivar No. /Bunch No./Bunch Hand Dwarf Double 8.7 129 17.3 Grand Nain 8.3 136 17.0 P-Value 0.068 0.7076 0.9560 Medium Gold Finger 9.5 az 138.0 a 17.6 a Ice Cream 8.2 a 136.0 a 16.2 a Cardaba 6.3 b 74.0 b 11.7 b Raja Puri 6.0 b 88.4 b 17.6 a P-Value 0.0058 0.0059 0.0500 Tall Sweetheart 8.6 134 18.0 Pisang Ceylon 8.5 117 16.0 P-Value 0.8000 0.1556 0.8033 zAny two means within a row not followed by the same letter are significantly different at P< 0.05.

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Table. 2. 39. Mean survivability (%) of dwarf, medium and tall Cavendish and non-Cavendish bananas cultivated at GREC, Fairhope, AL Mean Survivability (%)

2013-2014 2014-2015 Cultivar Dwarf Double 100 83 Dwarf Cavendish 100 83 Dwarf Green 100 100 Grand Nain 83 83 Dwarf Red 50 50 Medium Cardaba 100 100 Gold Finger 100 100 Ice Cream 100 100 Raja Puri 100 100 Veinte Cohol 16 16 Tall Pisang Ceylon 100 100 Saba 100 100 Sweetheart 100 100

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Pseudostem

Blade

Midrib

Petiole

Sheath

Sucker or ratoon plant

Figure 2. 1. Anatomy of aerial vegetative portions of a banana plant

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Whorl

Bunch

Hand

Finger

Rachis

Figure 2. 2. Anatomy of a banana bunch without the bell or male bud

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0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

Tem

pera

ture

(˚C

)

Month

Figure 2. 3. Long-Term Mean Monthly Maximum and Minimum Temperatures in Fairhope, AL, USA

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Figure 2. 4. Emerged flowers of inflorescence of banana cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL.

Figure 2. 5. Dwarf banana cultivars 12 weeks after DFM at the Gulf Coast Research and Extension Center, Fairhope, AL

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111

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Ambient

Soil

Tem

pera

ture

°C

Figure 2. 6. Ambient and soil temperatures in banana field From July, 2013 through November, 2014 at the Gulf Coast Research and Extension Center, Fairhope, AL

Month

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Figure 2. 7. Bananas regenerated from the rhizome in May, 2015 after uncharacteristically low temperatures in late December, 2013 and early January, 2014 at the Gulf Coast Research and Extension Center, Fairhope, AL.

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Figure 2. 8. Banana cultivars which belong to the Cavendish subgroup cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL

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Figure 2. 9. Laminal leaf shredding due to high winds of banana cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL

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Figure 2. 10. Developing bunch from Double (AAA) dwarf banana cultivars cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL

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Figure 2. 11. Harvest banana bunch from Grand Nain (AAA) banana cultivated at the Gulf Coast Research and Extension Center, Fairhope, AL

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Figure 2. 12. Developing Cardaba banana bunch prior to harvest in December, 2015 at the Gulf Coast Research and Extension Center, Fairhope, AL

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Figure 2. 13. Developing bunch from a Gold Finger (AAAB) exhibiting symptoms of chill damage prior to harvest in December, 2015 at the Gulf Coast Research and Extension Center, Fairhope, AL

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Figure 2. 14. Developing bunch from Sweetheart (AABB) cultivar prior to harvest in December, 2015 at the Gulf Coast Research and Extension Center, Fairhope, AL

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Chapter III

Concepts to Improve Sustainability of non-Cavendish

bananas cultivated in the subtropics of Coastal Alabama

Bananas possess unique potential as a specialty crop to enhance sustainability of

farm operations because of their global demand and the development of cultivars that are

more cold tolerant and have shorter production cycles. In the global market bananas are

known to require considerable inputs making their production cost prohibitive for smaller

farm operations. To mitigate these demands, innovative production practices must be

sought. Reflective mulches have been used to enhance lighting in production systems to

improve yield and quality of fruit crops and cover crops have been used in rotations to

increase crop diversity, improve soil quality, moisture retention and a source of organic

matter and nutrients. Reflective mulches and cover crops were selected and their effects

on banana phenology were determined in two experiments. In experiment one; white

polyethylene fabric and silver reflective film panels were installed on opposing sides of a

group of three banana plants to form an experimental unit. A control treatment which

received no reflective mulch was included in the study. The study followed a randomized

complete block design and contained six replications. In experiment two, hairy vetch and

Crimson clover along with a natural cover control formed the basis of a second study.

Bananas bunches of the white reflective mulch treatment were 27% and 15% heavier in

the reflective mulch treatments compared to bananas bunches of the control and were

produced on pseudostems that were 12% and 3% taller respectively than bananas of the

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control treatment. Leaf area of silver and white mulch treatments were increased by 8%

and 16% respectively than the control. Light radiation was enhanced in the lower canopy

of banana plants of the reflective mulch treatments. Flower emergence in the white fabric

mulch treatment occurred 5 d earlier than the control whereas flower emergence in the

silver mulch treatment was delayed by 26 d when compared to the control. Crimson

clover and hairy vetch produced bananas with pseudostems that were 20% and 8% taller

respectively than those of the control. Banana leaf area was 24% greater in the Crimson

clover treatment compared to the control while leaf area of the hairy vetch treatment was

10% larger. Reflective mulches and cover crops provided small gains in increasing

sustainability of niche market bananas. Reflective mulches resulted in earlier floral

emergence. Though banana plant vigor was slightly increased by cover crop usage, more

time is needed for cover crops to affect change to physical structure of the soil.

Introduction

Farmland in Alabama is being traded for development as many farmers are no

longer able to sustain their operations (Farmers Market Authority; Lu et al., 2000;

Nickerson et al., 2012). This not only necessitates crop importation from perhaps

thousands of miles and the use of fossil fuels it also presents a challenge to rural

communities because farmers are increasingly unable to reinvest in the community to

enhance the local economy. Crop diversity is a means to increase economic sustainability

of farm operations (Farmers Market Authority). Bananas offer a potential source for crop

diversity as banana fruit as well as containerized banana plants may be cultivated and

retailed by farmers as an alternative commodity to increase the economic sustainability of

their operations. The “Buy Fresh, Buy Local” campaign conducted by the Alabama

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Farmers Market Authority allows farmers to plant a diversity of crops and sell them at

farmers markets and grocers, while encouraging consumers to purchase fresher, better

tasting produce that also provides significant health benefits. A diverse crop planting

creates niche markets by allowing growers to produce crops locally that have traditionally

been imported. Banana fruit production is a new technology in the Southeast region that

offers a potential source for crop diversity because 1) Demand for the crop. Bananas are

the number one import fruit crop in the US with import value rising from $ 1 billion in

2006 to nearly $ 2 billion in 2010. Global banana production in 2011 was estimated at

106,058,470 metric tons and has increased 33% since 2005 making bananas the fourth

most important crop worldwide (Foastat, 2016). In many countries, bananas and

plantains (Musa sp.) are an important staple, as both a food source and critical source of

income and they are vital to the economies of developing nations (Abdul-Baki et al.

1997; Fonsah et al, 2004; Surendar et al., 2007). 2) The climate along the gulf coast of

Alabama is conducive for banana plant development. Temperatures in the region remain

within the cardinal temperature range for banana production for approximately 7 months.

During the times when temperatures fall below this range conditions are not usually

lethal to the plant. 3) Banana cultivation has expanded beyond tropical boundaries due

largely to the development of cold-tolerant, short-cycle cultivars (Lahav and Lowengart,

1998).

In large scale commercial production, banana crops require copious amounts of

inputs such as fertilizer, irrigation, and pest control. However, there has been conflicting

reports as to whether bananas require such high levels of resources (Turner et al., 2007).

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Notwithstanding, innovative production practices can be investigated to preserve the

sustainability that niche market bananas offer.

Innovation one: Reflective Mulch

In order that bananas reach maturity before the late frost, flower emergence

should begin during the month of July through August to provide sufficient time for

maturity of the developing bunch. The use of innovative production practices can be

investigated for their potential to decrease cropping cycles to encourage harvesting within

the interval of early and late frosts and conform to an annual cropping system found in

crops such as peach and apple. Plastic mulch and fabrics have previously been evaluated

for use in deterring insects that cause damage to plants or vector disease-causing agents

such as fungi or bacteria. Improved yields of tomatoes were found as a result of colored

mulches (Csizinszky et al., 1995). Aluminum mulches have been shown to repel thrips

and aphids – two important disease-vector organisms (Adlerz and Everett, 1968; Brown

and Brown, 1992; Wolfenbarger and Moore, 1968). More recently, white reflective fabric

improved light environment, increased photosynthetic activity by as much as 95% and

increased yield by 18% in mature, low-density ‘d’ Anjou’ pear orchards (Einhorn et al.,

2012).

Theoretically, increased planting density increases light interception by a

corresponding increase in leaf area index (LAI) which leads to improved yield (Robinson

and Galán Saúco, 2010; Robinson and Nel, 1989). However, delayed cropping cycles

and increased plant height in high density plantings are the result slower LER and an

increased number of leaves cycle-1 (Chundawat et al., 1983; Daniells et al., 1985;

Robinson and Nel, 1989; Turner, 1982). Increased light penetration reduces shading which

will increase LER (Robinson, 1996). This is the reason lower density plantings (<2,000 plants ha-

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1) are desired in some regions in the subtropics (Robinson and Nel, 1989). Additionally,

researchers have stated that decreased photosynthetic activity observed in leaves below the fifth

position on the banana leaf profile is due to aging of the photosynthetic apparatus. Leaves in

positions 2 -5 are the most recent of the banana canopy profile and are the most

photosynthetically active (Robinson and Galán Saúco, 2010). Rate of photosynthesis

begins to decline at leaf 6 and below. It is possible that increased senescence could be

the result of shading (Khan et al., 2000). Chlorophyll a and b in shade plants often

increases but photosynthesizing efficiency is lowered (Baldi et al., 2012). Leaf

senescence, a largely genetic factor (Yoshida, 1962), is characterized by leaf yellowing as

a result of chlorophyll degradation (Schelbert et. Al. 2009). Components of the degraded

chlorophyll are redistributed and used elsewhere in the plant (Masclaux-Daubresse et al.,

2008). In densely populated monocultures such as found in banana production, leaves of

the upper canopy receive full sun while lower profile leaves receive partial shade due to

blocking of solar radiation by leaves in the upper canopy. Shaded leaves adjust to

increasing shade so that a positive carbon balance is maintained, but as more leaves are

added in the upper canopy shade is increased and leaves cannot adequately compensate

for reduced solar radiation and subsequently, leaf senescence is induced (Brouwer et al.,

2012). Foliar longevity influences NSL which can shorten the cropping cycle by

enhancing the amount of dry matter produced if values are optimal. At the time of bunch

formation higher NSL improves maturation of the developing bunch. Bananas require a

minimum of 4 leaves to affect full maturity of a developing bunch.

Innovation two: Cover Crop Usage

Cover crops usage is one of the most important sustainable practices used in

global management strategies in agricultural systems and leads to improved soils,

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increased organic matter, and increased yield of target crops (Baligar et al 2006; JC

Robinson, 1996; Lu et al, 2000; Tixier et al 2011). Though cover crop usage in crop

production is not a new technology, there has been a surge in the incorporation of cover

crops in agricultural systems as it reduces inputs and suppresses pests by reintroducing

biodiversity (Tixier et al. 2011) and, in some cases eliminates the use of pesticides,

controls soil erosion, and reduces depletion of natural resources (Lu et al 2000).

Intensive cultural practices used in export banana production systems are usually

carried out on bare ground and therefore require large inputs such as pesticides and

fertilizers and the use thereof present challenges for delicate environmental systems

around the world (Bonan and Prime, 2001). Use of cover crops increases sustainability

by lowering inputs more effectively than some conventional cultural practices such as the

use of polyethylene mulch. Hairy vetch (Vivivia villosia) reduced N usage by 250 lbs

acre-1 less than that polyethylene mulch (Abdul-Baki and Teasdale, 1997) and saved $150

acre-1 in inputs.

A suitable cover crop should produce sufficient biomass in order to compete with

weeds for resources while not competing with the main crop and are usually evaluated in

terms of yield performance of a main crop in relation to the main crop cultivated on bare

ground (Costello and Altieri, 1994; Picard et al., 2010; Tixier et al., 2010).

The objective of this study is to determine the effects of reflective mulch

treatments and cover crop usage on the phenology/physiology of developing banana

plants. The hypothesis is that both main crop (bananas) and secondary crop (cover crop)

can be mutually cultivated without creating adverse effects on the phenology of the main

crop.

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Materials and Methods

Reflective mulch

Musa AAB (Mysore subgroup) ‘Mysore’ bananas obtained from tissue culture

(Agri-Starts Inc, Apopka, FL) were planted on raised beds 0.9 m wide and 0.15 m high.

Bananas were set at a within row spacing of 2.4 m on 10 July, 2014. Experimental plots

consisted of three banana plants. Silver reflective high density polyethylene film (Wilson

Orchard and Vineyard Supply Yakima, WA) with a thickness of 1 mil and white woven

polypropylene ground cover fabric at thickness of 0.1 kg·m-1 were used to form panels

with length of 7.3 m and width of 2 m. To improve durability of the silver metallic

mulch, white, woven polypropylene fabric was attached to the underside. Mulch panels

were installed on 20 April 2015. Panels were placed parallel to and on both sides of the

raised beds 0.6 m from the base of the pseudostem of the central plant and fastened in

place using metal stakes (Figures 3. 1. and 3. 2.). As the control, centipede sod was

allowed to persist uncovered by a mulch treatment and growth was controlled with

periodic applications of herbicide (Figure 3. 3.). A randomized complete block design

was used. A block was 30 m in length and contained three experimental units that were

spaced 4.3 m apart. Blocks (rows) were set on 6 m centers. Spacing was selected to

prevent influence of one treatment over another. Bananas received approximately 50 mm

water week-1. Bananas were fertilized according to the recommendations of the

Agricultural and Environmental Services Laboratories of the University of Georgia,

USA.

The parent crop (PC) which are bananas that were planted in the first season

succumbed to low temperatures of the winter. Absolute minimum temperature fell to -10

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°C in January, 2014. Ratoon plants however. (R1) or suckers were generated from the PC

rhizome. Winter-damaged Pseudostems of the PC were cut to a height of 0.5 m and

suckers were selected to replace the PC on 20 April 2015. All banana plants reached the

mature vegetative stage which is indicated by the production of mature leaves or the first

F10 leaf (leaf 10 cm in width) by 18 March 2015. Phenotypical data were collected on 55,

93, 135, 163, and 219 days from emergence of mature leaf (DFM) and consisted of

Pseudostem height (measured from base of the plant to the bifurcation formed by the top

two leaf petiole bases), pseudostem circumference at 30 cm above the ground, laminal

length and width (widest portion) of the third leaf of the plant profile, phyllochron or leaf

emergence rate (LER) as measured by the number of fully expanded leaves generated

month-1, number of standing leaves present, leaf area index (LAI) calculated from

equation 1. Soil temperature and soil moisture data were collected using an external

temperature sensor and a WaterScout SM 100 sensor interfaced with a WatchDog 1200

Microstation datalogger (Spectrum Technologies, Aurora, IL) at each experimental plot.

Both temperature and moisture probes were set at a depth of 20 cm.

Equation 1: l × w × 0.83/ (UGA) where l is laminal length and w is laminal width

multiplied by correction divided by UGA which is the unit ground area. Other

phenotypical data that were collected upon flowering are: days to flower emergence

(DFE) (emergence occurs when the first set of flowers of the inflorescence has been

exposed), pseudostem height at flower emergence, pseudostem circumference at flower

emergence.

Light measurements and photosynthetic activity were collected using a TPS-2

photosynthesis analyzer (PP systems, Amherst, MA). Light measurements were taken at

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the central plant at 55 days from mature leaf (DFM). Light and reflectance were

measured at 60 cm above ground and approximately 60 cm from the pseudostem facing

south. This series of measurements was repeated on the opposite side of the plant. A

PLC4 broad leaf cuvette was used to measure photosynthetic activity from a leaf area of

2.5 cm2. Readings were taken from the second, fourth and bottom leaves (leaves 7 or 8)

of the profile from the central plant.

Temperature of the plants was taken from the pseudostem of the central plant 1 m

above ground on 28 August 2015 at 10:00 am using an infrared temperature meter

(Spectrum Technologies, Inc. Aurora, IL). With a SPAD meter, chlorophyll readings

were taken from leaves 3 and 5 from both laminal halves on all three plants in the plot.

This resulted in 12 SPAD readings plot-1.

Cover crop

An on-farm study to determine the effects of two cover crops on the phenology

of Musa ABB ‘Dwarf Orinoco’ bananas was established at the Oak Hill Tree Farm in

Grand Bay, AL, (30° 31’ 56.3952” Latitude and -88° 20’ 29.9862” Longitude ). The

designated area was formerly pasture land and the soil type was a Heidel sandy loam.

Crimson clover (Trifolium incarnatum) and hairy vetch (Vivivia villosia) cover crop

treatments were seeded at recommended rates in 6 m × 7.3 m experimental plots and the

experimental plots were arranged in a completely randomized design. A control

experimental plot consisted of the natural, pre-established cover that was ~ 60%

bahiagrass (Paspalum notatum). Soil samples were collected prior to seeding to

determine initial organic matter content, soil fertility and lime requirements. Another soil

sample was taken near the end of the season. Biomass samples were collected after cover

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crops reach full bloom by clipping plants near soil surface in two 0.1 m2 quadrangle area

dimensions in each experimental plot. Biomass samples were oven-dried to determine C

and N content. Cover crops were allowed to persist and decompose on the soil surface.

Each experimental plot contained 5 plants. A single banana plant was set in the center of

each plot. On opposing sides of the central plant a row consisting of 2 bananas was

established at a distance of 3 m. Banana pants in the row were set at a 2.4 m within row

spacing and were equidistant from the central plant. This resulted in a spacing of 7 m2·

plant-1. Drip irrigation consisted of 16 mm polyethylene tubing with two manually-

installed emitters at a spacing of 2.4 m for delivery at each plant. Emitters were design to

deliver 7.6 L·h-1. Bananas received 25 mm water week-1. Fertility was supplied by hand

following recommendations of the Agricultural and Environmental Services Laboratories

of the University of Georgia, USA. Ambient and soil temperatures were monitored using

WatchDog A-Series Dataloggers (Spectrum Technologies, Aurora, IL). Cover crop and

control experimental plots were mowed on four occasions after cover crop biomass had

completely senesced and the previously established Bahia grass and other weed species

became dominant. Mowed plant material was allowed to remain on the surface of each

plot for the benefit of nutrient recycling and moisture retention. Foliar sampling

consisted of extracting 3 leaf sections 2.5 cm in width form the widest portion of the

lamina beginning at the midrib to the laminal edge. Sections were taken from the 2nd and

3rd positioned leaves of each plant in a plot and resulted in 15 leaf sections plot-1. Banana

growth data were collected from the centermost plant in each experimental plot and

consisted of growth parameter data such as pseudostem length, pseudostem

circumference, leaf area, and leaf emergence rate.

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Statistics

An analysis of variance was performed on all responses using PROC GLIMMIX

in SAS version 9.4 (SAS Institute, Cary, NC). The experimental design was a completely

randomized design with a factorial arrangement of cultivar and days after mature leaf

emergence. Days after emergence of mature leaves were analyzed as repeated measures.

Where residual plots and a significant COVTEST statement using the HOMOGENEITY

option indicated heterogeneous variance among treatments, a RANDOM statement with

the GROUP option was used to correct heterogeneity. For counted responses, the

normality assumption for ANOVA was tested using studentized residuals and the tests for

normality statistics in PROC UNIVARIATY. Data were considered non-normal when the

Shapiro-Wilk, the Kolmogorov-Smirnov, the Anderson-Darling, and the Cramér-von

Mises tests were all significant. Non-normal counts were analyzed using either the

Poisson or negative binomial distribution depending on which distribution resulted in a

Pearson Chi-Square / DF value closest to value of 1.0. Differences among treatments

were determined using the Shaffer Simulated method.

Results and Discussion

Reflective Mulch

Reflective mulch treatments had no significant effect on bunch weight or total

hand weight though values of reflective mulch treatments were consistently higher

numerically than the control (Table 3. 1.). Bananas cultivated using silver and white

reflective mulches produced bunches that were 27% and 15% heavier respectively than

bananas in the control treatment. Total hand weight of bananas from the silver and white

reflective mulches were 24% and 20% heavier respectively than the control while

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production efficiency was higher in bananas of the silver reflective treatment. Bananas of

the control treatment had 33% higher production efficiency than bananas of the white

reflective mulch treatment. Both bunch weight (0.9398 kg) and total hand weight

(0.8375 kg) were strongly correlated to soil moisture. The weight of individual hands

were 21% higher in bananas from the white reflective fabric treatments then from

bananas of the control treatment while hands from the silver reflective treatment were

12% higher than hands of the control treatment (Table 3. 2.). There were only slight

differences in finger length and width among treatments though values of reflective

mulches were numerically higher than the control. Soil moisture was moderately or

strongly correlated to average hand number, finger length and width while soil

temperature was weakly or moderately correlated to these variables.

At final sampling (219 DFM) neither pseudostem length, pseudostem

circumference, nor HCR were significantly affected by reflective treatments (Table 3. 3.).

Banana plants of the reflective mulch treatments were larger than the control according to

pseudostem length and width but values were not significantly affected. Silver reflective

mulch produced bananas with a 12% greater length than the control while white

reflective mulch produced bananas plants with pseudostems that were 3% longer than

banana pseudostems of the control. Statistical similarities in both pseudostem length and

circumference resulted in no statistical difference in height: circumference (HCR).

There was only an 8% increase in leaf area in the bananas of the silver reflective

mulch treatment over bananas of the control while bananas of the control treatment

produced leaves with a 16% greater leaf area than bananas of the white fabric (Table 3.

4.). CLN and LER values were virtually the same among treatments.

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At 55 DFM (Table 3. 5.), light reflectance and interception were significantly

increased in the reflective mulch treatments over the control treatment when measured

between 1200 h and 1230 h. Light reflected in the white fabric treatment was increased

by 3 fold compared to the control while light interception was increased by 57%

compared to the control. Additionally, there was a 3.3-fold increase in reflected light

compared to the control and a 60% increase in light interception.

Rate of photosynthesis (Table 3. 6.) at 55 DFM of the reflective mulch treatments

was not significantly increased in the 2nd, 4th or 8th lamina above those of the control. As

expected, overall rate of net photosynthesis (μmol·m-2·s-1) decreased from the 2nd to the

8th lamina; however, there was a 2-fold increase in photosynthetic rate over the control.

Values of Chlorophyll content taken at 93 DFM, as expressed in SPAD values, was

numerically higher in the reflective mulch treatments compared to the control but

differences among treatments were not significant. There was a 1.4% increase in

temperature of pseudostems while white fabric created < 1°C increase.

Flower emergence occurred significantly earlier in the white reflective treatment

than the silver reflective treatment or the control (Table 3. 7.). Flower emergence

occurred 5 d sooner in the white reflective treatments compared to the control while

flower emergence in the silver mulch treatment occurred 26 d later than in the control

treatments.

Discussion

Phenological/physiological measurements of bananas of the reflective mulch

treatments were often numerically higher when compared to the control but differences

among treatments were often not significant. In a previous study, reflective fabrics did

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not cause ‘d’ Anjou’ pear trees to be physiologically more advanced than the control

which received no reflective fabric (Einhorn et al., 2012).

These slight increases in growth in bananas of the reflective mulch treatments

over the control may be responsible for earlier flower emergence found in white mulch

treatments over the control though only a 5 d difference. According to Table 3.6., light

reflectance and light interception were significantly increased above those of the control;

however, silver reflective mulch did not hasten flower emergence but resulted in a delay

of 26 d. This could have been the result of bananas leaves receiving incident light

radiation in excess of their photosynthesizing capacity resulting in damage directly to the

photosynthetic apparatus leading to photoinhibition, which might ultimately lead to

delayed flower emergence. (Baroli and Melis, 1998; Powles, 1984). When light radiation

is excessive, bananas will execute a light-avoidance response of leaf folding, but this

response was circumvented in a sense due to light radiation coming from opposing

sources.

Cover Crop Experiment

Hairy vetch (Table 3. 8.) had the highest fresh weight (177.18 g) but this did not

result in hairy vetch having the highest dry weight which was found in Crimson Clover

treatment (131.2 g). The control cover treatment that consisted of ~ 60% bahiagrass

had a fresh and dry weight of 49.7 g and 23.8 g respectively. Hairy vetch treatment

contributed the highest percentage of N at 3.15% followed by Crimson Clover (1.88%)

and natural (control) cover (1.6%). There was no significant difference in percent C

among the treatments but C:N ratio of hairy vetch treatment was lower than crimson

clover (21:1) and the control cover treatment (20:1). Low C:N ratio of hairy vetch

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resulted in faster decomposition and less residence time on the soil surface. Hairy vetch

was expected to supply significantly more N (143 kg·ha-1) compared to Crimson Clover

(121 kg·ha-1) and natural cover control (41 kg·ha-1).

Soil samples collected prior to cover crop application revealed that soil pH (Table

3. 9.) was similar in all plots (~ 5.5). There was no significant difference in soil macro

nutrients phosphorus, potassium, or magnesium. Calcium was significantly lower in soil

samples collected from the hairy vetch treatment than the control but similar to Crimson

Clover treatments.

Percent soil organic matter was slightly higher numerically in hairy vetch

treatment compared to natural cover (1.64) and Crimson Clover (1.62). Additionally,

there were no significantly differences found in percent soil C or percent soil N among all

treatments.

A second soil analysis taken in November, 2014 revealed a significant decrease in

pH (5.1) in the hairy vetch treatment (Table 3. 10.). Increased soil acidity might have

caused a corresponding decrease in Mg as this nutrient is made less available as soil pH

decreases.

Foliar nutrient content of the banana plants was compared among treatments

though no sufficiency ranges are available for sampling that occurs at bunch formation

(Table 3. 11.). No significant differences were found in foliar nutrient content due to a

cover crop treatment. Range of foliar Mn (404.4-566.2) Na (259.8 – 447.2), and Mg

(0.144-0.172) were the broadest of the foliar nutrients.

Growth parameters were not significantly affected by cover crop treatments

compared to the control treatments; however, bananas of the cover crop treatments were

135

consistently larger numerically than bananas of the control treatment (Table 3. 12.). Leaf

area of bananas cultivated Crimson Clover treatments was 24% greater than bananas of

the control while bananas of the hairy vetch treatment were 10% larger than the bananas

of the control treatment. Crimson clover and hairy vetch also produced taller bananas

(20% and 8% respectively) than the control, while pseudostem circumference of bananas

of the Crimson Clover and hairy vetch treatments were 20 % and 12 % greater than

bananas of the control treatment.

Number of standing leaves , LER and total leaves produced were similar for all

treatments (Table 3. 12.).

Discussion

It is not surprising to see no significant differences among treatments. Benefits of

cover crop usage in agricultural systems are measured over several seasons and often

require several years to determine. To expedite the selection process of cover crops some

studies have employed the use of models to predict the performance of cover cropping

systems (Rioche et al., 2012; Tixier et al., 2010). Models have been developed to predict

weed populations, weed/main crop interactions, and genotype/environmental interactions

(Holst et al., 2007; Paolini et al., 2006). A study conducted by Tixier et al. (2010)

described the use of a model-based system for the selection of cover crops in banana

production. The authors developed a model called SIMBA-CC which was based on

radiation reception. The authors determined that the most suitable species in terms of

their ability to maximize competition with weed species while minimizing completion

with banana crop were Alysicarpus ovalifolius, Cynodon dactylon, and Chamaecrista

rotundifolia.

136

Models use for prediction of how bananas in a banana-cover crop production

system can be useful, but the more definitive method is actual field trials. More

experimentation will be needed to determine the effects of Crimson Clover and Hairy

Vetch on the growth and yield of banana plants.

Cover crop usage as a sustainable practice is also used in natural or organic

production. An added premium can be placed on bananas that are certified organic or

are grown naturally. Integration of organic or natural cultural practices were thought

not to provide enough nutrients for commercial banana production but integration of

natural resources in banana production at various stages of banana plant development

could actually result in higher yield while enhancing soil quality (Manivannan and

Selvamani, 2014). More recently studies confirmed banana production using 100%

organic inputs can achieve sufficient yield of high quality fruit that can command

premium prices in the market (Manivannon and Selvamani, 2014). Records of trade

volume are sparse but the USDA was able to estimate total value of organic bananas

imported to the US as $214.5 million in 2013. In the US organic production has

increased by 34% since 2000. Organic production of bananas is increasing globally.

Ecuador (Table 3. 13.) is the leading producer of organic bananas at over 20,000 ha

devoted to production.

Organic banana production is thought to be good for the overall health of

agrosystems and people specifically, but they must understandably follow strict

guidelines as found in the guidelines for production, processing, labelling, and marketing

of organically produced foods (FAO). Third party certification systems in agriculture

have proliferated. Third party certification was marketed on the premise that consumers

137

in wealthy, first world nations will pay extra for a product that is produced in ways that

reflect their values. This is a segment of consumers that make purchases that are in

keeping with deeply held values or beliefs. Currently, organic and fair trade certified

bananas are set at a premium price and are presented as high-end. In 2011, production in

this market was 55,000 MT per year or 11% of the total EU market (Van der Waal and

Moss, 2011). Rainforest certification carried by Chiquita Brands International bananas

are high-end and account for 15% of the market share. In the 1990’s Chiquita formed an

alliance with Sustainable Agricultural Network (SAN). Out of this collaboration was

formed the Rainforest Alliance – an American, non-governmental agency concerned with

promotion of sustainable practices. This greatly enhanced their brand as the Chiquita –

Rainforest Alliance was considered one of the most strategic environmental plans (Etsy

and Winston, 2009; Van der Waals and Moss, 2011).

Conclusions

The two innovations discussed reveal marginal potential in increasing

sustainability of subtropical production of non-Cavendish bananas for a niche market.

Reflective mulches were ineffective in increasing banana plant vigor, increasing leaf

surface area, leaf longevity (NSL), or LER which hastens arrival at a CLN range

predictive of flower emergence. White mulch decreased DTE significantly compared to

the no cover control and silver mulch treatment. DTE was significantly increased in the

silver mulch treatments compared to the white mulch or control. Effects of reflective

mulch treatments in decreasing or increasing DTE may have more to do with soil

moisture and soil temperature than increased light radiation in the under canopy of

bananas. Reflective mulch usage in bananas may be more impactful where cultivars with

138

exceptionally brief production cycles such as ‘Veinte Cohol’ are being grown.

Cover crop usage in banana production has been strongly encouraged. It has the

potential of lowering inputs such as irrigation, fertility, and pests such as weeds, insects

and disease. Benefits of cover crop usage may not be realized in large commercial

plantations were Cavendish is being produced because nutrients would not be made

available at the rates required by the industry. These operations require excessive amount

of irrigation and fertilizer –especially K and N. However, studies have shown that

banana production using 100% organic inputs like cover crop usage produced comparable

yields to a system utilizing conventional production methods. Nevertheless, small farmer

operation could benefit from cover crop usage because bunch yield would be necessarily

smaller would not demand the level nutrient (N) supply that bananas require for the

Cavendish market.

Cover crops in this single-year study did not affect soil composition or structure

to the point of increasing plant vigor. Use of cover crops is a paradigm shift for many

farm managers and appreciable benefits to the soil will be realized after long-term

practice, but demand for naturally or organically grown products continues to increase.

Bananas that meet the requirements of a particular certification can receive a premium

price.

139

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Table 3. 1. Effect of Silver Reflective Mulch and White Reflective Mulch on Yield and Production Efficiency of Musa (AAB) ‘Mysore’ Bananas at the Gulf Coast REC Fairhope, AL. 2013.

Bunch Total Hand Production Weight Weight Efficiency Treatment (kg) (kg) (bunch wt./Rachis wt) No Cover 5.4ns 4.6ns 6.0ns Silver Reflective 6.9 5.7 7.5 White Reflective 6.2 5.5 4.5 Correlation Soil Temperature 0.3415 0.3769 0.0234 Soil Moisture 0.9398 0.8375 0.851

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Table 3. 2. Effect Silver Reflective and White Reflective Mulch on Bunch Characteristics of Musa (AAB) ‘Mysore’ Bananas at the Gulf Coast REC, Fairhope, AL. 2013.

Number Avg Hand Finger Finger of Weight Length Width

Treatment Hands (g) (mm) (mm) No Cover 9ns 510.5ns 77.6ns 21.6ns Silver Reflective 9.0 570.2 83.5 22.1 White Reflective 8 620.2 88.8 22.0 Correlation Soil Temperature 0.5836 0.5042 0.4393 0.483 Soil Moisture 0.0303 0.8803 0.7807 0.5966

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Table 3. 3. The Effects of Silver Reflective Film and White Reflective Mulch on Pseudostem Length, Pseudostem Circumference,and Height: Circumference Ratio on Musa sp. (AAB) ‘Mysore’Banana at the Gulf Coast REC, Fairhope, AL. Pseudo- Pseudo- Height:

stem stem Circum. Length Circum. Ratio Treatment (cm) (cm) Silver Film 260.60 59.0 4.44 White Fabric 239.80 53.0 4.52 No Cover 232.66 51.2 4.48 P-Value 0.3634 0.1931 0.9550

148

Table 3. 4. The Effects of Silver Reflective Film and White Reflective Mulch on Leaf Area, Number of Leaves Present, Cumulative Leaf Number and Leaf Emergence Rate on Musa sp. (AAB) ‘Mysore’ Banana at the Gulf Coast REC, Fairhope, AL.

3rd Pos- ition Leaf Leaf Number Cumulative Emergence Area Leaves Leaf Rate

Treatment (cm2) Present Number (Leaves month-1) Silver Film 12,590 13.60 33.33 4.33 White Fabrice 10,027 13.60 33.67 4.00 No Cover 11,665 13.00 32.20 4.00 P-Value 0.1263 0.8945 0.2975 0.1439

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Table 3. 5. Light Reflectance of white fabric and silver film as measure by photosynthetically active radiation (PAR). Gulf Coast REC, Fairhope, AL.

East West East West Reflect. Reflect. Intercept Intercept Trt Temp °C (μmol·m-2·s-1) (μmol·m-2·s-1) (μmol·m-2·s-1) (μmol·m-2·s-1) White Fabric 29.97 388.67 az 419.17 a 728.2 1379.8 a Silver Film 29.50 507.33 a 381.83 a 840 1316.2 a No Cover 28.60 104.00 b 101.50 b 738.0 606.3 b P-Value 0.8279 0.0006 0.0015 0.9082 0.0148 zAny two means within a row not followed by the same letter are significantly different at P< 0.05 according to Shaffer Simulated method.

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Table 3. 6. Spad Reading and Net Photosynthesis of the 2nd, 4th , and 8th Lamina of Musa sp. (AAB) ‘Mysore’ Banana at the Gulf Coast REC, Fairhope, AL. Net Photo- Net Photo- Net Photo- Mean synthesisx synthesis synthesis Net Photo- Spad 2nd Lamina 4th Lamina 8th Lamina synthesis Treatment Readingy (μmol·m-2·s-1) (μmol·m-2·s-1) (μmol·m-2·s-1) (μmol·m-2·s-1) No Cover 52.32 19.0 16.55 12.63 16.5 White Fabric 53.36 21.35 14.52 30.95 26.2 Silver Film 53.52 20.74 12.7 9.88 13.98 P-Value 0.5951 0.7847 0.7435 0.2544 0.1080 ySpad readings were taken at 135 DFM xPhotosynthesis was measured at 55 DFM

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Table 3. 7. Effect of Silver Reflective and White Reflective Mulches on Timing of Flower Emergence of Musa (AAB) ‘Mysore’ Bananas at the Gulf Coast REC, Fairhope, AL. 2013. Days to Emergence Treatment (DTE) Bare Ground 221bz Silver Reflective 247a White Reflective 216c Correlation Pr > F Temperature <.0001 Moisture 0.0409 zAny two means within a row not followed by the same letter are significantly different at P< 0.05 according to Shaffer Simulated method.

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Table 3. 8. Fresh weight, dry weight, %N and %C of crimson clover (CC), hairy vetch (HV), and Bahia grass (BG)sod control plots at the Oak Hill Tree Farm, Grand Bay, AL, May, 2015. Cover Crop Fresh Dry Treatment Weight Weight Nitrogen Carbon Nitrogen (g) (g) (%) (%) kg ha-1 HV 177.2 az 41.1 b 3.2 a 42.0 143 a CC 131.3 b 61.5 a 1.9 b 39.3 121 a BG 49.7 c 23.9 c 1.6 b 31.5 41 b P-Value 0.0004 0.0021 0.0021 0.057 0.0013 zAny two means within a row not followed by the same letter are significantly different at P< 0.05 according to Shaffer Simulated method.

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Table 3. 9. First analysis of elemental soil nutrient composition of experimental plots containing Crimson Clover (CC), Hairy Vetch (HV), and Bahia grass (BG) control treatments at the Oak Hill Tree Farm, Grand Bay, AL, November, 2013. Cover Crop Trt pH P K Mg Ca Al BG 5.7 119.4 128.2 63 703.6 az 205.2 CC 5.5 126.6 125.4 58.4 615.2 ab 212.6 HV 5.5 134.8 113.4 54.2 597.4 b 215.8 Sig. 0.1163 0.7723 0.2865 0.0573 0.0341 0.5571 B Cu Fe Mn Na Zn BG 0.1 1.02 17.6 15.6 37.2 1.18 CC 0.1 1.22 20.6 16.4 36.6 1.12 HV 0.12 1.12 20.0 12.6 34.4 1.20 Sig. 0.4096 0.7089 0.0509 0.2648 0.3403 0.9366 zAny two means within a row not followed by the same letter are significantly different at P< 0.05 according to Shaffer Simulated method.

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Table 3. 10. Second analysis of elemental soil nutrient composition of experimental plots containing Crimson Clover (CC), Hairy Vetch (HV), and Bahia grass (BG) control treatments at the Oak Hill Tree Farm, Grand Bay, AL,– November, 2014. Cover Crop Treatment pH P K Mg Ca BG 5.62 a 134.2 176.6 70.4 az 709.4 CC 5.5 a 155.6 164 72.4 a 616.8 HV 5.18 b 145.2 152.6 50.20 b 510.2 Sig. 0.0025 0.7575 0.4412 0.0394 0.1906 Organic C:N Carbon Nitrogen Matter Ratio (%) (%) (%) HV 1 0.08 1.72 13:1 BG 0.964 0.082 1.64 12:1 CC 0.946 0.076 1.62 12:1 Sig. 0.4438 0.547 0.3895 . zAny two means within a row not followed by the same letter are significantly different at P< 0.05 according to Shaffer Simulated method.

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Table 3. 11. Foliar nutrient composition of bananas cultivated in Crimson Clover (CC), Hairy Vetch (HV), and Bahia grass (BG) sod control treatment at the Oak Hill Tree Farm, Grand Bay, AL, 2014. Cover Crop Trt Ca K Mg P Al B BG 0.382 3.204 0.158 0.202 10.8 6.59 CC 0.390 3.140 0.172 0.200 12.2 7.39 HV 0.406 3.120 0.144 0.200 10.8 6.99 Sig. 0.8309 0.8811 0.132 0.9801 0.9018 0.8935 Cu Fe Mn Na Zn BG 13.8 41.0 404.4 259.8 25.4 CC 13.8 42.4 537.4 447.2 24.4 HV 16.4 41.2 566.2 339.0 23.4 Sig. 0.219 0.8688 0.056 0.1121 0.9663

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Table 3. 12. Effect of Crimson Clover and Hairy Vetch Treatments on growth parameters of ‘Dwarf Orinoco’ Bananas in Grand Bay, AL, 2014. Pseudo- Pseudo- Leaf stem stem Laminal Laminal

Length Circum Length Width Cover Crop (cm) (cm) (cm) (cm) Bahai grass Control 49.30 13.14 49.75 24.10 Crimson Clover 58.02 15.25 54.81 26.87 Hairy Vetch 53.60 14.26 52.98 25.32 Significance Cover Crop 0.068 0.1155 0.2217 0.2394 DFP <.0001 <.0001 <.0001 0.0015 Cover x DFP 0.8061 0.6703 0.6258 0.5117 Number Cumulative

Leaf Standing Leaf Area(cm2) Leaves LER Number

Bahai grass Control 1238.70 6.12 3.28 10.20 Crimson Clover 1590.44 6.76 3.31 10.36 Hairy Vetch 1362.90 6.36 3.36 10.20 Cover Crop 0.223 0.1597 0.9911 0.8392 DFP <.0001 <.0001 0.476 <.0001 Cover x DFP 0.5349 0.0703 0.9926 0.9413

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Table 3. 13. 1Production Area of Organically Produced Bananas of Leading Countries in Latin America and the Caribbean. Country Total Area (Hectares) Ecuador 20,033 Dominican Rep. 14,953 Peru 5,092 Costa Rica 3,409 Mexico 238 Guatemala 72 Panama 22 Jamaica 7 1Statistics provided by The World of Organic Agriculture and Trends 2010.

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Figure 3. 1. White reflective mulch used to increase light interception of lower canopy leaves

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Figure 3. 2. Silver reflective mulch used to increase light interception of lower canopy leaves.

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Figure 3. 3. Control treatment with no reflective fabric or film cover.